strlwr, strupr in c

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++;

   }

}