C Program To Replace Lowercase Characters By Uppercase Or Vice-Versa.

This program checks each character one by one. If the character is in lowercase, then it is converted into uppercase. But if it is in uppercase then converts into lowercase. The source code is successfully compiled and run on any operating system.

#include <stdio.h>

#include <ctype.h>

int main()

{

char sentence[100];

int count, ch, i;

printf("Enter One or Multiple Sentence:\n\n\t");

for (i = 0; (sentence[i] = getchar()) != '\n'; i++)

{

        ;

}

sentence[i] = '\0';

count = i;

printf("\n\nConverting Lowercase to Uppercase or Vice Versa:\n\n\t");

for (i = 0; i < count; i++)

{

ch = islower(sentence[i])? toupper(sentence[i]):tolower(sentence[i]);

putchar(ch);

}

printf("\n");

}