#include<stdio.h>
#include<string.h>
main()
{
	char s[100];
	printf("enter the string in upper case\n");
	gets(s);
	strlwr(s);
	printf("the string in lower case letters is:\n");
	puts(s);
	
}
     
           
Note: Need to be arranged in compiler after copied
   

 OutPut:

enter the string in upper case COMPUTER the string in lower case letters is: computer