C programming is a powerful language widely used for its efficiency and control. One of the fundamental tasks in C programming is performing arithmetic operations, such as addition. In this article, we’ll explore three distinct methods of C program for Addition of two numbers, each with its own approach and explanation. These methods will help beginners understand different ways to handle simple operations and demonstrate how to implement them efficiently.

Three ways to write a program for “Addition of two numbers in C”

Method 1) Addition of two numbers in C using Variables

The simplest way to add two numbers in C is by using basic arithmetic operations with variables. This method involves declaring two variables to store the numbers, adding them together, and then displaying the result.

Code Example

#include <stdio.h>

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

    // Input two numbers from the user
    printf("Enter first number: ");
    scanf("%d", &num1);
    printf("Enter second number: ");
    scanf("%d", &num2);

    // Add the numbers
    sum = num1 + num2;

    // Display the result
    printf("The sum of %d and %d is %d\n", num1, num2, sum);

    return 0;
}

Explanation of the Code

1. Include the Standard I/O Library: #include <stdio.h> allows the program to use input and output functions like printf and scanf.
2. Declare Variables: int num1, num2, sum; are integer variables to store the user inputs and the result.
3. Input Numbers: scanf("%d", &num1); reads the input from the user and stores it in num1. The same is done for num2.
4. Perform Addition: sum = num1 + num2; adds the two numbers and stores the result in sum.
5. Display Result: printf("The sum of %d and %d is %d\n", num1, num2, sum); prints the result to the console.

Method 2) Addition of two numbers in C using Functions

In C, functions allow for code reuse and modularity. By using functions, we can separate the logic of addition from the main program, making the code cleaner and more manageable.

Code Example

#include <stdio.h>

// Function to add two numbers
int addNumbers(int a, int b) {
    return a + b;
}

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

    // Input two numbers from the user
    printf("Enter first number: ");
    scanf("%d", &num1);
    printf("Enter second number: ");
    scanf("%d", &num2);

    // Call the function to add the numbers
    sum = addNumbers(num1, num2);

    // Display the result
    printf("The sum of %d and %d is %d\n", num1, num2, sum);

    return 0;
}

Explanation of the Code

1. Function Definition: int addNumbers(int a, int b) defines a function that takes two integers as arguments and returns their sum.
2. Function Call: In the main function, sum = addNumbers(num1, num2); calls addNumbers with num1 and num2 as arguments.
3. Separation of Concerns: This method separates the addition logic from input/output handling, improving code organization and readability.

Method 3) Addition of two numbers in C using Pointers

Pointers in C allow for direct memory access, and using them can provide a deeper understanding of how data is managed. This method demonstrates how to perform addition by manipulating pointers.

Code Example

#include <stdio.h>

// Function to add two numbers using pointers
void addNumbers(int *a, int *b, int *result) {
    *result = *a + *b;
}

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

    // Input two numbers from the user
    printf("Enter first number: ");
    scanf("%d", &num1);
    printf("Enter second number: ");
    scanf("%d", &num2);

    // Call the function to add the numbers using pointers
    addNumbers(&num1, &num2, &sum);

    // Display the result
    printf("The sum of %d and %d is %d\n", num1, num2, sum);

    return 0;
}

Explanation of the Code

1. Pointer Function Definition: void addNumbers(int *a, int *b, int *result) takes pointers to integers. It uses these pointers to access and modify the values directly.
2. Dereferencing: *result = *a + *b; calculates the sum by dereferencing the pointers to access the actual values.
3. Pointer Usage: addNumbers(&num1, &num2, &sum); passes the addresses of num1, num2, and sum to the function, allowing it to modify the sum variable directly.