C programming code

#include <stdio.h>

#include<conio.h> 

void main()

{

   char text[100], blank[100];

   int c = 0, d = 0;

   clrscr();

   printf("Enter some text\n");

   gets(text);

   while (text[c] != '\0')

   {

      if (!(text[c] == ' ' && text[c+1] == ' ')) 

      {

        blank[d] = text[c];

        d++;

      }

      c++;

   }

  blank[d] = '\0';

  printf("Text after removing blanks\n%s\n", blank);

  getch();

}

Output of program:

C programming code using pointers

#include <stdio.h>

#include <string.h>

#include <stdlib.h>

#include<conio.h>

#define SPACE ' '

void main()

{

   char string[100], *blank, *start;

   int length, c = 0, d = 0;

   clrscr();

   printf("Enter a string\n");

   gets(string);

   length = strlen(string);

   blank = string;

   start = (char*)malloc(length+1);

   if ( start == NULL )

   exit(EXIT_FAILURE);

   while(*(blank+c))

   {

      if ( *(blank+c) == SPACE && *(blank+c+1) == SPACE )

      {}

      else

      {

         *(start+d) = *(blank+c);

d++;

      }

      c++;

   }

   *(start+d) = '\0';

   printf("%s\n", start);

   free(start);     

   getch();

}

C programming code

#include <stdio.h>

#include <string.h>

#include <malloc.h>

#include<conio.h>

void main()

{

   char first[100], second[100], *temp;

   clrscr();

   printf("Enter the first string\n");

   gets(first);

   printf("Enter the second string\n");

   gets(second);

   printf("\nBefore Swapping\n");

   printf("First string: %s\n",first);

   printf("Second string: %s\n\n",second);

   temp = (char*)malloc(100);

   strcpy(temp,first);

   strcpy(first,second);

   strcpy(second,temp);

   printf("After Swapping\n");

   printf("First string: %s\n",first);

   printf("Second string: %s\n",second);

   getch();

}

Output of program:

Here we will change string case with and without strlwr, strupr functions.

strlwr in c

#include <stdio.h>

#include <string.h>

#include<conio.h> 

void main()

{

    char string[] = "Strlwr in C";

    clrscr();

    printf("%s\n",strlwr(string));

    getch();

}

strupr in c

#include <stdio.h>

#include <string.h>

#include<conio.h>

void main()

{

    char string[] = "strupr in c";

    clrscr();

    printf("%s\n",strupr(string));

    getch();

}

Change string to upper case without strupr

#include <stdio.h>

#include<conio.h> 

void upper_string(char*);

void main()

{

   char string[100];

   clrscr();

   printf("Enter a string to convert it into upper case\n");

   gets(string);

   upper_string(string);

   printf("Entered string in upper case is \"%s\"\n", string);

   getch();

}

void upper_string(char *string)

{

   while(*string)

   {

       if ( *string >= 'a' && *string <= 'z' )

       {

          *string = *string - 32;

       }

       string++;

   }

}

Change string to lower case without strlwr

#include <stdio.h>

#include<conio.h> 

void lower_string(char*);

void main()

{

   char string[100];

   clrscr();

   printf("Enter a string to convert it into lower case\n");

   gets(string);

   lower_string(string);

   printf("Entered string in lower case is \"%s\"\n", string);

   getch();

}

void lower_string(char *string)

{

   while(*string)

   {

      if ( *string >= 'A' && *string <= 'Z' ) 

      {

         *string = *string + 32;

      }

      string++;

   }

}

C program to convert string to integer: It is frequently required to convert a string to an integer in applications. String should consists of digits only and an optional '-' (minus) sign at beginning for integers. For string containing other characters we can stop conversion as soon as a non digit character is encountered but in our program we will handle ideal case when only valid characters are present in string. Library function atoi can be used to convert string to an integer but we will create our own function.

C programming code

#include <stdio.h>

#include<conio.h> 

int toString(char []);

void main()

{

  char a[100];

  int n;

  clrscr();

  printf("Input a valid string to convert to integer\n");

  scanf("%s", a);

  n = toString(a);

  printf("String  = %s\nInteger = %d\n", a, n);

  getch();

}

int toString(char a[]) 

{

  int c, sign, offset, n;

  if (a[0] == '-') 

  {  

  sign = -1;

  }

  if (sign == -1) 

  { 

    offset = 1;

  }

  else 

  {

    offset = 0;

  }

  n = 0;

 for (c = offset; a[c] != '\0'; c++) 

 {

  n = n * 10 + a[c] - '0';

 }

 if (sign == -1) 

{

  n = -n;

 }

 return n;
}

C program to sort a string in alphabetic order: For example if user will enter a string "programming" then output will be "aggimmnoprr" or output string will contain characters in alphabetical order.

C programming code

#include <stdio.h>

#include<conio.h>

#include <stdlib.h>

#include <string.h>

void sort_string(char*);

void main()

{

   char string[100];

   clrscr();

   printf("Enter some text\n");

   gets(string);

   sort_string(string);

   printf("%s\n", string);

   getch();

}

void sort_string(char *s)

{

   int c, d = 0, length;

   char *pointer, *result, ch;

   length = strlen(s);

   result = (char*)malloc(length+1);

   pointer = s;

   for ( ch = 'a' ; ch <= 'z' ; ch++ )

   {

      for ( c = 0 ; c < length ; c++ )

      {

         if ( *pointer == ch )

         {

            *(result+d) = *pointer;

            d++;

         }

         pointer++;

      }

      pointer = s;

   }

   *(result+d) = '\0';

   strcpy(s, result);

   free(result);

}

Output of program:

C substring code

#include <stdio.h>

#include<conio.h>

#include <malloc.h>

char* substring(char*, int, int);

void main() 

{

   char string[100], *pointer;

   int position, length;

   clrscr();

   printf("Enter a string\n");

   gets(string);

   printf("Enter the position and length of substring\n");

   scanf("%d%d",&position, &length);

   pointer = substring( string, position, length);

   printf("Required substring is \"%s\"\n", pointer);

   free(pointer);

   getch();

}

/*C substring function: It returns a pointer to the substring */

char *substring(char *string, int position, int length) 

{

   char *pointer;

   int c;

   pointer = malloc(length+1);

   if (pointer == NULL)

   {

      printf("Unable to allocate memory.\n");

      exit(EXIT_FAILURE);

   }

   for (c = 0 ; c < position -1 ; c++) 

   string++; 

   for (c = 0 ; c < length ; c++)

   {

      *(pointer+c) = *string;      

      string++;   

   }

  *(pointer+c) = '\0';

  return pointer;

}

Output of program:

C code for all substrings of a string

#include <stdio.h>

#include <string.h>

#include<conio.h>

#include <malloc.h>

char* substring(char*, int, int);

void main() 

{

   char string[100], *pointer;

   int position = 1, length = 1, temp, string_length;

   clrscr();

   printf("Enter a string\n");

   gets(string);

   temp = string_length = strlen(string);

   printf("Substring of \"%s\" are\n", string);

   while (position <= string_length)

   {

      while (length <= temp)

      {

         pointer = substring(string, position, length);

         printf("%s\n", pointer);

         free(pointer);

         length++;

      }

      temp--;

      position++;

      length = 1;

   }

  getch();

}

Output of program:

c program to remove or delete vowels from a string, if the input string is "c programming" then output will be "c programming". In the program we create a new string and process entered string character by character, and if a vowel is found it is not added to new string otherwise the character is added to new string, after the string ends we copy the new string into original string. Finally we obtain a string without any vowels.

C programming code

#include <stdio.h>

#include <string.h>

#include<conio.h> 

int check_vowel(char);

int main()

{

  char s[100], t[100];

  int i, j = 0;

  clrscr();

  printf("Enter a string to delete vowels\n");

  gets(s);

  for(i = 0; s[i] != '\0'; i++) 

  {

    if(check_vowel(s[i]) == 0) 

    {      

      t[j] = s[i];

      j++;

    }

  }

  t[j] = '\0';

  strcpy(s, t);    

  printf("String after deleting vowels: %s\n", s);

  getch();

}

 int check_vowel(char c)

{

  switch(c) 

   {

    case 'a':

    case 'A':

    case 'e':

    case 'E':

    case 'i':

    case 'I':

    case 'o':

    case 'O':

    case 'u':

    case 'U':

      return 1;

    default:

      return 0;

  }

}

C programming code using pointers

#include<stdio.h>

#include<stdlib.h>

#include<string.h>

#include<conio.h>

#define TRUE 1

#define FALSE 0

int check_vowel(char);

void main()

{

   char string[100], *temp, *pointer, ch, *start;

   printf("Enter a string\n");

   gets(string);

   temp = string;

   pointer = (char*)malloc(100);

   if( pointer == NULL )

   {

      printf("Unable to allocate memory.\n");

      exit(EXIT_FAILURE);

   }

   start = pointer;

   while(*temp)

   {

      ch = *temp;

      if ( !check_vowel(ch) )

      {

         *pointer = ch;

         pointer++;

      }

      temp++;

   }

   *pointer = '\0';

   pointer = start;

   strcpy(string, pointer); /* If you wish to convert original string */

   free(pointer);

   printf("String after removing vowel is \"%s\"\n", string);

   getch();

}

int check_vowel(char a)

{

   if ( a >= 'A' && a <= 'Z' )

   a = a + 'a' - 'A';

   if ( a == 'a' || a == 'e' || a == 'i' || a == 'o' || a == 'u')

      return TRUE;

   return FALSE;

}

C program for palindrome

#include <stdio.h>

#include <string.h>

#include<conio.h> 

void main()

{

   char a[100], b[100];

   clrscr();

   printf("Enter the string to check if it is a palindrome\n");

   gets(a);

   strcpy(b,a);

   strrev(b);

   if( strcmp(a,b) == 0 )

      printf("Entered string is a palindrome.\n");

   else

      printf("Entered string is not a palindrome.\n");

   getch();

}

Output of program:

Palindrome number in c

#include <stdio.h>

#include<conio.h> 

void main()

{

   int n, reverse = 0, temp;

   clrscr();

   printf("Enter a number to check if it is a palindrome or not\n");

   scanf("%d",&n);

   temp = n;

   while( temp != 0 )

   {

      reverse = reverse * 10;

      reverse = reverse + temp%10;

      temp = temp/10;

   }

   if ( n == reverse )

      printf("%d is a palindrome number.\n", n);

   else

      printf("%d is not a palindrome number.\n", n);

   getch();

}

C program for palindrome without using string functions

#include <stdio.h>

#include <string.h>

#include<conio.h> 

void main()

{

   char text[100];

   int begin, middle, end, length = 0;

   clrscr();

   gets(text);

   while ( text[length] != '\0' )

   length++;

   end = length - 1;

   middle = length/2;

   for( begin = 0 ; begin < middle ; begin++ )

   {

      if ( text[begin] != text[end] )

      {

         printf("Not a palindrome.\n");

         break;

      }

      end--;

   }

   if( begin == middle )

   printf("Palindrome.\n");

   getch();

}

C program check palindrome

#include <stdio.h>

#include<conio.h> 

int is_palindrome(char*);

void copy_string(char*, char*);

void reverse_string(char*);

int string_length(char*);

int compare_string(char*, char*);

void main()

{

   char string[100];

   int result;

   clrscr();

   printf("Enter a string\n");

   gets(string);

   result = is_palindrome(string);

   if ( result == 1 )

   printf("\"%s\" is a palindrome string.\n", string);

   else

   printf("\"%s\" is not a palindrome string.\n", string); 

   getch();

}

int is_palindrome(char *string)

{

   int check, length;

   char *reverse;

   length = string_length(string);    

   reverse = (char*)malloc(length+1);    

   copy_string(reverse, string);

   reverse_string(reverse);

   check = compare_string(string, reverse);

   free(reverse);

   if ( check == 0 )

   return 1;

   else

   return 0;

}

int string_length(char *string)

{

   int length = 0;  

   while(*string)

   {

      length++;

      string++;

   }

   return length;

}

void copy_string(char *target, char *source)

{

   while(*source)

   {

      *target = *source;

      source++;

      target++;

   }

   *target = '\0';

}

void reverse_string(char *string) 

{

   int length, c;

   char *begin, *end, temp;

   length = string_length(string);

   begin = string;

   end = string;

   for ( c = 0 ; c < ( length - 1 ) ; c++ )

   end++;

    for ( c = 0 ; c < length/2 ; c++ ) 

   {        

      temp = *end;

      *end = *begin;

      *begin = temp;

      begin++;

      end--;

   }

}

int compare_string(char *first, char *second)

{

   while(*first==*second)

   {

      if ( *first == '\0' || *second == '\0' )

         break;

      first++;

      second++;

   }

   if( *first == '\0' && *second == '\0' )

      return 0;

   else

      return -1;

}

C programming code

#include <stdio.h>

#include <string.h>

#include<conio.h> 

void main()

{

   char arr[100];

   clrscr();

   printf("Enter a string to reverse\n");

   gets(arr);

   strrev(arr);

   printf("Reverse of entered string is \n%s\n",arr);

   getch();

}

C program to reverse a string using pointers

 Now we will invert string using pointers or without using library function strrev.

#include<stdio.h>

#include<conio.h> 

int string_length(char*);

void reverse(char*);

void main() 

{

   char string[100];

   clrscr(); 

   printf("Enter a string\n");

   gets(string);

   reverse(string);

   printf("Reverse of entered string is \"%s\".\n", string);

   getch();

}

void reverse(char *string) 

{

   int length, c;

   char *begin, *end, temp;

   length = string_length(string);

   begin = string;

   end = string;

    for ( c = 0 ; c < ( length - 1 ) ; c++ )

      end++;

    for ( c = 0 ; c < length/2 ; c++ ) 

   {        

      temp = *end;

      *end = *begin;

      *begin = temp;

      begin++;

      end--;

   }

}

int string_length(char *pointer)

{

   int c = 0;

   while( *(pointer+c) != '\0' )

    c++;

    return c;

}

C program to reverse a string using recursion

#include <stdio.h>

#include <string.h>

#include<conio.h> 

void reverse(char*, int, int);

void main()

{

   char a[100];

   gets(a);

   reverse(a, 0, strlen(a)-1);

   printf("%s\n",a);

   getch();

}

void reverse(char *x, int begin, int end)

{

   char c;

   if (begin >= end)

   return;

   c = *(x+begin);

   *(x+begin) = *(x+end);

   *(x+end) = c;

   reverse(x, ++begin, --end);

}

This program concatenates strings, for example if the first string is "c " and second string is "program" then on concatenating these two strings we get the string "c program". To concatenate two strings we use strcat function of string.h, to concatenate without using library function see another code below which uses pointers.

C programming code

#include <stdio.h>

#include <string.h>

#include<conio.h> 

void main()

{

   char a[100], b[100];

   clrscr();

   printf("Enter the first string\n");

   gets(a);

   printf("Enter the second string\n");

   gets(b);

   strcat(a,b);

   printf("String obtained on concatenation is %s\n",a);

   getch();

}

String concatenation without strcat

#include <stdio.h>

#include<conio.h> 

void concatenate_string(char*, char*);

void main()

{

    char original[100], add[100];

    clrscr();

    printf("Enter source string\n");

    gets(original);

    printf("Enter string to concatenate\n");

    gets(add);

    concatenate_string(original, add);

    printf("String after concatenation is \"%s\"\n", original);

    getch();

}

void concatenate_string(char *original, char *add)

{

   while(*original)

      original++;

   while(*add)

   {

      *original = *add;

      add++;

      original++;

   }

   *original = '\0';

}

C program to copy a string

#include<stdio.h>

#include<string.h>

#include<conio.h> 

void main()

{

   char source[] = "C program";

   char destination[50];

   clrscr();

   strcpy(destination, source);

   printf("Source string: %s\n", source);

   printf("Destination string: %s\n", destination);

   getch();

}

c program to copy a string using pointers

#include<stdio.h>

#include<conio.h>

#include<string.h> 

void copy_string(char*, char*);

void main()

{

    char source[100], target[100];

    clrscr();

    printf("Enter source string\n");

    gets(source);

    copy_string(target, source);

    printf("Target string is \"%s\"\n", target);

    getch();

}

void copy_string(char *target, char *source)

{

   while(*source)

   {

      *target = *source;

      source++;

      target++;

   }

   *target = '\0';

}

1. What is data structure?
Answer:
A data structure is a way of organizing data that considers not only the items stored, but also their relationship to each other. Advance knowledge about the relationship between data items allows designing of efficient algorithms for the manipulation of data.

2. List out the areas in which data structures are applied extensively?
Answer:
 Compiler Design,
 Operating System,
 Database Management System,
 Statistical analysis package,
 Numerical Analysis,
 Graphics,
 Artificial Intelligence,
 Simulation

3. What are the major data structures used in the following areas : RDBMS, Network data model & Hierarchical data model.
Answer:
 RDBMS                         – Array  (i.e. Array of structures)
 Network data model      – Graph
 Hierarchical data model – Trees

4. If you are using C language to implement the heterogeneous linked list, what pointer type will you use?
Answer:
The heterogeneous linked list contains different data types in its nodes and we need a link, pointer to connect them. It is not possible to use ordinary pointers for this. So we go for void pointer. Void pointer is capable of storing pointer to any type as it is a generic pointer type.
       
5. Minimum number of queues needed to implement the priority queue?
Answer:
Two. One queue is used for actual storing of data and another for storing priorities.

6. What is the data structures used to perform recursion?
Answer:
Stack. Because of its LIFO (Last In First Out) property it remembers its ‘caller’ so knows whom to return when the function has to return. Recursion makes use of system stack for storing the return addresses of the function calls. 
Every recursive function has its equivalent iterative (non-recursive) function. Even when such equivalent iterative procedures are written, explicit stack is to be used. 

7. What are the notations used in Evaluation of Arithmetic Expressions using prefix and postfix forms?
Answer:
Polish and Reverse Polish notations.

8. Convert the expression ((A + B) * C – (D – E) ^ (F + G)) to equivalent Prefix and Postfix notations.
Answer:
Prefix Notation:
^ - * +ABC - DE + FG 
Postfix Notation:
AB + C * DE - - FG + ^ 

9. Sorting is not possible by using which of the following methods?
(a) Insertion     
(b) Selection     
(c) Exchange      
(d) Deletion
Answer:
(d) Deletion.
Using insertion we can perform insertion sort, using selection we can perform selection sort, using exchange we can perform the bubble sort (and other similar sorting methods). But no sorting method can be done just using deletion.

10. A binary tree with 20 nodes has_______null branches?
Answer:
21
Let us take a tree with 5 nodes (n=5) 

It will have only 6 (i.e., 5+1) null branches. In general, A binary tree with n nodes has exactly n+1null nodes. 

11. What are the methods available in storing sequential files?
Answer:
 Straight merging,
 Natural merging,
 Polyphase sort,
 Distribution of Initial runs.

12. How many different trees are possible with 10 nodes ?
Answer:
1014
For example, consider a tree with 3 nodes (n=3), it will have the maximum combination of 5 different (i.e., 23 - 3 = 5) trees.

In general:
If there are n nodes, there exist 2n-n different trees. 

13. List out few of the Application of tree data-structure?
Answer:
 The manipulation of Arithmetic expression,
 Symbol Table construction,
 Syntax analysis.

14. List out few of the applications that make use of Multilinked Structures?
Answer:
 Sparse matrix,
 Index generation.

15. In tree construction which is the suitable efficient data structure?
(a) Array           
(b) Linked list              
(c) Stack           
(d) Queue   
(e) none
Answer:
(b) Linked list

16. What is the type of the algorithm used in solving the 8 Queens problem?
Answer:
Backtracking

17. In an AVL tree, at what condition the balancing is to be done? 
Answer:
If the ‘pivotal value’ (or the ‘Height factor’) is greater than 1 or less than –1.

18. What is the bucket size, when the overlapping and collision occur at same time?
Answer:
One. If there is only one entry possible in the bucket, when the collision occurs, there is no way to accommodate the colliding value. This results in the overlapping of values.

19. Traverse the given tree using Inorder, Preorder and Postorder traversals.
Answer:

 Inorder : D H B E A F C I G J
 Preorder: A B D H E C F G I J
 Postorder: H D E B F I J G C A

20. There are 8, 15, 13, 14 nodes were there in 4 different trees. Which of them could have formed a full binary tree?
Answer:
15. 
In general:
There are 2n-1 nodes in a full binary tree.
By the method of elimination:
Full binary trees contain odd number of nodes. So there cannot be full binary trees with 8 or 14 nodes, so rejected. With 13 nodes you can form a complete binary tree but not a full binary tree. So the correct answer is 15.
*Note:
Full and Complete binary trees are different. All full binary trees are complete binary trees but not vice versa. 

21. In the given binary tree, using array you can store the node 4 at which location?
Answer:

At location  6

22. Sort the given values using Quick Sort?

65 70 75 80 85 60 55 50 45
Answer:
Sorting takes place from the pivot value, which is the first value of the given elements, this is marked bold. The values at the left pointer and right pointer are indicated using L and R respectively.

65 70L 75 80 85 60 55 50 45R

Since pivot is not yet changed the same process is continued after interchanging the values at L and R positions

65 45 75L 80 85 60 55 50R 70

65 45 50 80L 85 60 55R 75 70

65 45 50 55 85L 60R 80 75 70


65 45 50 55 60R 85L 80 75 70

When the L and R pointers cross each other the pivot value is interchanged with the value at right pointer. If the pivot is changed it means that the pivot has occupied its original position in the sorted order (shown in bold italics) and hence two different arrays are formed, one from start of the original array to the pivot position-1 and the other from pivot position+1 to end.

60L 45 50 55R 65 85L 80 75 70R

55L 45 50R 60 65 70R 80L 75 85

50L 45R 55 60 65 70 80L  75R 85

In the next pass we get the sorted form of the array.

45 50 55 60 65 70 75 80 85


23. For the given graph, draw the DFS and BFS?
Answer:

 BFS:  A X G H P E M Y J

 DFS: A X H P E Y M J G

24. Classify the Hashing Functions based on the various methods by which the key value is found. 
Answer:
 Direct method,
 Subtraction method,
 Modulo-Division method,
 Digit-Extraction method,
 Mid-Square method,
 Folding method,
 Pseudo-random method.  

25. What are the types of Collision Resolution Techniques and the methods used in each of the type?
Answer:
 Open addressing (closed hashing),
The methods used include:
Overflow block,
 Closed addressing (open hashing)
The methods used include:
Linked list,
Binary tree…

26. In RDBMS, what is the efficient data structure used in the internal storage representation?
Answer:
B+ tree. Because in B+ tree, all the data is stored only in leaf nodes, that makes searching easier. This corresponds to the records that shall be stored in leaf nodes.    

27. Draw the B-tree of order 3 created by inserting the following data arriving in sequence – 
            92  24  6  7  11  8  22  4  5  16  19  20  78
Answer:

28. Of the following tree structure, which is, efficient considering space and time complexities?
(a) Incomplete Binary Tree
(b) Complete Binary Tree      
(c) Full Binary Tree
Answer:
(b) Complete Binary Tree. 
By the method of elimination:
Full binary tree loses its nature when operations of insertions and deletions are done. For incomplete binary trees, extra storage is required and overhead of NULL node checking takes place. So complete binary tree is the better one since the property of complete binary tree is maintained even after operations like additions and deletions are done on it.  

29. What is a spanning Tree?
Answer:
A spanning tree is a tree associated with a network. All the nodes of the graph appear on the tree once. A minimum spanning tree is a spanning tree organized so that the total edge weight between nodes is minimized.

30. Does the minimum spanning tree of a graph give the shortest distance between any 2 specified nodes?
Answer:
No.
Minimal spanning tree assures that the total weight of the tree is kept at its minimum. But it doesn’t mean that the distance between any two nodes involved in the minimum-spanning tree is minimum.

31. Convert the given graph with weighted edges to minimal spanning tree. 
Answer:

the equivalent minimal spanning tree is:

           
32. Which is the simplest file structure?
(a) Sequential 
(b) Indexed 
(c) Random
Answer:
(a) Sequential

33. Whether Linked List is linear or Non-linear data structure?
Answer:

• According to Access strategies Linked list is a linear one.
• According to Storage Linked List is a Non-linear one.

34. Draw a binary Tree for the expression :

A * B - (C + D) * (P / Q)
Answer:

35. For the following COBOL code, draw the Binary tree?
01 STUDENT_REC.
     02 NAME.
          03 FIRST_NAME PIC X(10).
   03 LAST_NAME PIC X(10).

02 YEAR_OF_STUDY.
   03 FIRST_SEM PIC XX.
   03 SECOND_SEM PIC XX.
Answer: