Return values in C - Mini Project: Build & Apply

Return values

📖 Scenario: You are creating a simple calculator program in C that adds two numbers. You will write a function that returns the sum of two integers.

🎯 Goal: Build a C program with a function called add that takes two integers and returns their sum. Then call this function and print the result.

📋 What You'll Learn

Create a function named add that takes two int parameters

The add function must return the sum of the two integers

Call the add function from main with the values 5 and 7

Print the returned result using printf

💡 Why This Matters

🌍 Real World

Functions that return values are used everywhere in programming to calculate results and pass data between parts of a program.

💼 Career

Understanding return values is essential for writing reusable code and working with APIs, libraries, and complex software systems.

1

Create the add function signature

Write the function signature for a function called add that takes two int parameters named a and b and returns an int. Do not write the function body yet.

C

// Write the function signature for add here
// Your code here

Need a hint?

Function signature includes return type, function name, and parameters.

2

Define the add function body

Write the full definition of the add function that returns the sum of a and b. Use a return statement.

C

int add(int a, int b) {
    // Your code here
}

Need a hint?

Use return a + b; inside the function body.

3

Call add in main and store result

Write the main function. Inside it, call the add function with arguments 5 and 7, and store the result in an int variable named result.

C

int add(int a, int b) {
    return a + b;
}

int main() {
    // Your code here
    return 0;
}

Need a hint?

Call add(5, 7) and assign it to result.

4

Print the result

Add a printf statement in main to print the value of result followed by a newline. Use the format specifier %d.

C

int add(int a, int b) {
    return a + b;
}

int main() {
    int result = add(5, 7);
    // Your code here
    return 0;
}

Need a hint?

Use printf("%d\n", result); to print the sum.