C Program to Find the Sum of Three Numbers

In this article, we will write a C program to find the sum of three numbers.

The program takes three numbers from the user as input and prints their sum on the screen as output.

Sample Input:

Enter three numbers: 10 20 30

Output:

Sum of the three numbers is: 60

The following program shows how you can calculate the sum of three numbers in C programming:

// C program to add three numbers
#include <stdio.h>

int main() {

    int num1, num2, num3, res;

    printf("Enter three numbers: ");
    scanf("%d %d %d", & num1, & num2, & num3);

    // Calculate the sum
    res = num1 + num2 + num3;

    // Print the result
    printf("Sum of the three numbers is: %d", res);

    return 0;

}

Output:

Enter three numbers: 10 20 30
Sum of the three numbers is: 60

Code Explanation:

• The program takes three numbers from the user and stores them in num1, num2 and num3 variables respectively.
• To store the sum of the three variables we have declared a variable res.
• The sum of the three numbers is calculated using the addition operator(+) and stored in the res variable.
• Finally, the sum of the three numbers is printed on the screen using the printf() function.

Example 2: Find the Sum of Three Numbers using a Function

You can also define a function which takes three numbers as its arguments and returns their sum as a result.

See the implementation in the following program:

// C program to add three numbers using function
#include <stdio.h>

//Function declaration
int add(int, int, int);

int main() {

    int num1, num2, num3, res;

    printf("Enter three numbers: ");
    scanf("%d %d %d", & num1, & num2, & num3);

    // Call the add() function
    res = add(num1, num2, num3);

    // Print the result
    printf("Sum of the three numbers is: %d", res);

    return 0;

}

// User defined function for addition
int add(int a, int b, int c) {
    int result;
    result = a + b + c;
    return result;
}

Output:

Enter three numbers: 10 20 30
Sum of the three numbers is: 60

Code Explanation:

• The program takes three numbers from the user and stores them in num1, num2 and num3 variables.
• To get the sum of the three numbers, we have defined a function add(). The add() function takes three numbers as its arguments, calculates their sum and returns it.
• The sum returned by the add() method is stored in the res variable.
• Finally, the result is printed on the screen using the printf() function.

Thanks for reading.