using functions in c

To use functions in C, you need to follow these steps:

1. Function Declaration: Declare the function prototype before using it in the program. This includes the function name, return type, and parameter list (if any).

2. Function Definition: Define the function by writing the function body, which contains the statements that will be executed when the function is called.

3. Function Call: Call the function by using its name followed by parentheses. Pass any required arguments inside the parentheses.

Here is an example that demonstrates the usage of functions in C:

#include <stdio.h>

// Function declaration
int addNumbers(int a, int b);

int main() {
    int num1, num2, sum;

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

    // Function call
    sum = addNumbers(num1, num2);

    printf("Sum = %d\n", sum);

    return 0;
}

// Function definition
int addNumbers(int a, int b) {
    int result;
    result = a + b;
    return result;
}

In this example, the addNumbers function is declared and defined. It takes two integers as arguments and returns their sum. Inside the main function, the user is prompted to enter two numbers. The addNumbers function is called with the user-inputted numbers as arguments, and the result is stored in the sum variable. Finally, the sum is printed to the console.

This is a basic example of using functions in C. You can define and use functions to modularize your code, make it more organized, and reuse code logic in different parts of your program.