C Program – Convert string from Uppercase to Lowercase!

Let’s write an useful C program today. This C Program will convert any Uppercase string to Lowercase.

For this, we are going to use tolower() function which is already available in C itself.

#include <stdio.h>

int main() {

	char mystr[100];
	int i=0;
		
	//print about the program
	printf("C Program to convert uppercase to lowercase\n");
    printf("Enter your full name in CAPS: ");
   	
   	//get the input string from user
   	fgets(mystr, 100, stdin);
   	
   	//loop through the string and convert into lower letters
    while( mystr[i] ) {
      //store back the lower letter to mystr
      mystr[i] = tolower(mystr[i]);
      i++;
   }    
   
   //print the lower letters
   printf("Lowercase: %s", mystr);
}

Read the comments in the above program to understand how it works.

Output of the above program will be:

C Program to convert uppercase to lowercase
Enter your full name in CAPS: AGURCHAND BABU
Lowercase: agurchand babu

Enjoy the day!