FAQs in C: Program to Add Two Numbers

Here’s a C program to add two numbers:

#include <stdio.h>

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

  // Prompt the user to enter two numbers
  printf("Enter two numbers: ");

  // Read the two numbers using scanf
  scanf("%d %d", &num1, &num2);

  // Calculate the sum
  sum = num1 + num2;

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

  return 0;
}

Explanation

Include the Standard Input-Output header file: #include <stdio.h> is used to include the standard input-output library which allows us to use functions like printf and scanf.

Declare the main function: int main() is the main function where the execution of the program begins.

Declare integer variables: int num1, num2, sum; declares three integer variables num1, num2, and sum.

Read inputs from the user:

• printf(“Enter the first number: “); prompts the user to enter the first number.
• scanf(“%d”, &num1); reads the integer input from the user and stores it in num1.
• printf(“Enter the second number: “); prompts the user to enter the second number.
• scanf(“%d”, &num2); reads the integer input from the user and stores it in num2.

Add the two numbers: sum = num1 + num2; calculates the sum of num1 and num2 and store the result in sum.

Print the result: printf(“The sum of %d and %d is %d\n”, num1, num2, sum); prints the values of num1, num2, and sum in a formatted string.

Return statement: return 0; indicates that the program ended successfully.

Algorithm:

Step 1: Start
Step 2: Declare two integer variables, num1 and num2.
Step 3: Declare an integer variable sum to store the result.
Step 4: Read the values of num1 and num2 from the user.
Step 5: Add num1 and num2, and store the result in sum.
Step 6: Print the value of sum.
Step 7: Stop

Explanation of the Algorithm

Step 1: Start

• Start indicates the beginning of the algorithm. This is where the process of adding two numbers begins.

Step 2: Declare two integer variables, num1 and num2.

• Declare two integer variables, num1 and num2: This step involves defining two variables that will hold the integer values entered by the user. These variables will store the two numbers that we want to add.

Step 3: Declare an integer variable sum to store the result.

• Declare an integer variable sum: In this step, we define another integer variable named sum that will hold the result of the addition of num1 and num2.

Step 4: Read the values of num1 and num2 from the user.

• Read the values of num1 and num2 from the user: This step involves taking input from the user. We prompt the user to enter two integer values which will be stored in the variables num1 and num2.

Step 5: Add num1 and num2 and store the result in sum.

• Add num1 and num2, and store the result in sum: In this step, we perform the addition of the two numbers stored in num1 and num2. The result of this addition is then stored in the variable sum.

Step 6: Print the value of sum.

• Print the value of sum: Here, we output the result of the addition to the user. This step involves displaying the value stored in the variable sum.

Step 7: Stop

• Stop: This step signifies the end of the algorithm. Once the result has been displayed, the process is complete, and the algorithm terminates.