Introduction
A calculator is a basic tool that helps us perform mathematical operations quickly & easily. A simple calculator can perform basic arithmetic operations such as addition, subtraction, multiplication, and division.
In this article, we will learn how to create a simple calculator program in C that can add, subtract, multiply & divide two numbers. Apart from that we will also learn the step by step approach with time and space complexity.
Approach: Simple Calculator Program Using Switch Statement
To create a simple calculator program in C, we will follow these steps:
-
Declare variables to store the two numbers & the result.
-
Display a menu of operations for the user to choose from (addition, subtraction, multiplication, division).
-
Use the scanf() function to read the user's choice & the two numbers.
-
Based on the user's choice, perform the corresponding mathematical operation using a switch statement.
-
Display the result of the calculation.
-
Ask the user if they want to perform another calculation.
-
Repeat steps 2-6 until the user chooses to exit the program.
Now we will look at a complete code for this calculator program in C :
- C
C
#include <stdio.h>
int main() {
float number1, number2;
char operation;
// Prompting user for input
printf("Enter two numbers: ");
scanf("%f %f", &number1, &number2);
printf("Enter an operation (+, -, *, /): ");
scanf(" %c", &operation); // Notice the space before %c to capture the previous newline character.
// Processing the operation using a switch statement
switch(operation) {
case '+':
printf("%.2f + %.2f = %.2f\n", number1, number2, number1 + number2);
break;
case '-':
printf("%.2f - %.2f = %.2f\n", number1, number2, number1 - number2);
break;
case '*':
printf("%.2f * %.2f = %.2f\n", number1, number2, number1 * number2);
break;
case '/':
if(number2 != 0.0) {
printf("%.2f / %.2f = %.2f\n", number1, number2, number1 / number2);
} else {
printf("Division by zero is not allowed.\n");
}
break;
default:
printf("Invalid operation.\n");
}
return 0;
}
You can also try this code with Online C Compiler
Output
Enter two numbers: 5 6
Enter an operation (+, -, *, /): +
5.00 + 6.00 = 11.00Explanation
-
Library Inclusion: We start by including the stdio.h library, which is necessary for input and output operations.
-
Main Function: The main function is the entry point of any C program.
-
Variable Declaration: We declare two floating-point variables number1 and number2 for the operands, and a character variable operation for the operator.
-
Input: The program prompts the user to enter two numbers and an operation. It uses scanf to read the input. The space before %c in the scanf function is crucial as it consumes any whitespace characters, including the newline left in the input buffer by previous inputs.
-
Switch Statement: The operations are processed using a switch statement. Each case checks for the operation entered (+, -, *, /) and performs the corresponding arithmetic operation, printing the result. The default case handles any invalid operations entered by the user.
- Handling Division by Zero: There is a specific check in the division case to ensure there is no division by zero, which would otherwise cause a runtime error.
569+ registered 
