C program to capitalize first character of each word in a string

In this program, we will learn how to capitalize each word of input string using C program?

This program will read a string and print Capitalize string, Capitalize string is a string in which first character of each word is in Uppercase (Capital) and other alphabets (characters) are in Lowercase (Small).

For example:
If input string is "hello friends how are you?" then output (in Capitalize form) will be "Hello Friends How Are You?".

Program to capitalize first character of each word in a string in C

#include <stdio.h>
#define MAX 100

int main()
{
    char str[MAX] = { 0 };
    int i;

    //input string
    printf("Enter a string: ");
    scanf("%[^\n]s", str); //read string with spaces

    //capitalize first character of words
    for (i = 0; str[i] != '\0'; i++) {
        //check first character is lowercase alphabet
        if (i == 0) {
            if ((str[i] >= 'a' && str[i] <= 'z'))
                str[i] = str[i] - 32; //subtract 32 to make it capital
            continue; //continue to the loop
        }
        if (str[i] == ' ') //check space
        {
            //if space is found, check next character
            ++i;
            //check next character is lowercase alphabet
            if (str[i] >= 'a' && str[i] <= 'z') {
                str[i] = str[i] - 32; //subtract 32 to make it capital
                continue; //continue to the loop
            }
        }
        else {
            //all other uppercase characters should be in lowercase
            if (str[i] >= 'A' && str[i] <= 'Z')
                str[i] = str[i] + 32; //subtract 32 to make it small/lowercase
        }
    }

    printf("Capitalize string is: %s\n", str);

    return 0;
}

Output

First run:
Enter a string: HELLO FRIENDS HOW ARE YOU?
Capitalize string is: Hello Friends How Are You?

Second run:
Enter a string: hello friends how are you?
Capitalize string is: Hello Friends How Are You?

Third run:
Enter a string: 10 ways to learn programming.
Capitalize string is: 10 Ways To Learn Programming.

In this example, we have used the following C language topics that you should learn: