C Program to Add Two Numbers Using Call by Reference

The program takes the two numbers from the user and passes the reference to the function where the sum is calculated. You may go through the topic below.

• C call by reference

#include <stdio.h>

//user-defined function
float addFunc(float *a, float *b)
{
  float sum;

  sum = *a + *b;

  return sum;
}

int main()
{
  float num1, num2, result;

  printf("Enter the first number: ");
  scanf("%f", &num1);

  printf("Enter the Second number: ");
  scanf("%f", &num2);

  result = addFunc(&num1, &num2);

  printf("Sum of the result: %f", result);

  return 0;
}

Output:

Enter the first number: 15.5
Enter the Second number: 20.5
Sum of the result: 36.000000

---

This is a simple C program that demonstrates the use of a user-defined function to add two floating-point numbers. Let’s break down the code:

Function Declaration:

<code>float addFunc(float *a, float *b)

• This line declares a function named addFunc that takes two float pointers (a and b) as parameters and returns a float value.

Function Definition:

<code>{ float sum; sum = *a + *b; return sum; }

• Inside the addFunc function, it calculates the sum of the values pointed to by a and b and returns the result.

Main Function:

int main()
{
    // Variable declaration
    float num1, num2, result;

    // Input from user
    printf("Enter the first number: ");
    scanf("%f", &num1);

    printf("Enter the Second number: ");
    scanf("%f", &num2);

    // Function call
    result = addFunc(&num1, &num2);

    // Output
    printf("Sum of the result: %f", result);

    return 0;
}

• The main function is the entry point of the program.
• It declares three float variables num1, num2, and result.
• It takes user input for num1 and num2 using scanf.
• Calls the addFunc function, passing the addresses of num1 and num2.
• Prints the result.

Execution:

• The program prompts the user to enter two floating-point numbers.
• It then calculates the sum of these numbers using the addFunc function.
• Finally, it prints the result to the console.

So, if the user enters, for example, 5.3 and 2.7, the program would output:

Enter the first number: 5.3
Enter the Second number: 2.7
Sum of the result: 8.000000

---