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.