C++ Switch-Based Calculator: +,-,*,/,%

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C++ Switch-Based Calculator: +,-,*,/

Hey guys! Today, we're diving into creating a simple yet powerful calculator using C++ and the switch statement. This calculator will perform basic arithmetic operations like addition, subtraction, multiplication, division, and modulus. It's a great project for beginners to understand control flow and basic input/output operations in C++. So, let's get started!

Understanding the Code

First, let's break down the C++ code snippet provided. This code takes an operator and two numbers as input and performs the corresponding operation using a switch statement. Here’s a detailed look:

#include <iostream>
using namespace std;
int main()
{
 char ch;
 int A;
 int B;
 cout<<"enter ch";
 cin>>ch;
 cout<<"enter first number";
 cin>>A;
 cout<<"enter secound number";
 cin>>B;
 switch(ch)
 {
 case '+':
 cout<<"result"<<A+B;
 break;
 case '-':
 cout<<"result"<<A-B;
 break;
 case '*':
 cout<<"result"<<A*B;
 break;
 case '/':
 cout<<"result"<<A/B;
 break;
 case '%':
 cout<<"result"<<A%B;
 break;
 default:
 cout<<"invalid operation";
 }
 return 0;
}

Explanation:

  • Including the Header: The line #include <iostream> includes the iostream library, which is essential for input and output operations in C++. It allows us to use objects like cout (for output) and cin (for input).
  • Using Namespace: using namespace std; simplifies our code by allowing us to use objects and functions from the standard namespace without explicitly specifying std:: before them. For example, we can use cout instead of std::cout.
  • Main Function: The int main() function is the entry point of our program. Execution begins here.
  • Declaring Variables: Inside the main function, we declare three variables:
    • char ch: This variable will store the operator entered by the user (+, -, *, /, or %).
    • int A: This variable will store the first integer input by the user.
    • int B: This variable will store the second integer input by the user.
  • Taking Input: We prompt the user to enter the operator and the two numbers using cout and store the inputs using cin.
    • cout<<"enter ch"; displays a message asking the user to enter the operator.
    • cin>>ch; reads the operator entered by the user and stores it in the ch variable.
    • cout<<"enter first number"; displays a message asking the user to enter the first number.
    • cin>>A; reads the first number entered by the user and stores it in the A variable.
    • cout<<"enter secound number"; displays a message asking the user to enter the second number.
    • cin>>B; reads the second number entered by the user and stores it in the B variable.
  • Switch Statement: The switch statement is used to perform different actions based on the value of the ch variable. Each case corresponds to a different operator.
    • case '+':: If the operator is '+', this case is executed. It calculates the sum of A and B and prints the result using cout.
    • case '-':: If the operator is '-', this case is executed. It calculates the difference between A and B and prints the result.
    • case '*':: If the operator is '*', this case is executed. It calculates the product of A and B and prints the result.
    • case '/':: If the operator is '/', this case is executed. It calculates the quotient of A and B and prints the result.
    • case '%':: If the operator is '%', this case is executed. It calculates the remainder of A divided by B and prints the result. This is the modulus operator.
    • default:: If the operator is none of the above, the default case is executed. It prints an "invalid operation" message.
  • Break Statement: The break statement is used to exit the switch statement after a case is executed. Without break, the program would continue to execute the subsequent case statements.
  • Return Statement: The return 0; statement indicates that the program has executed successfully.

Enhancing the Calculator

Now that we have a basic calculator, let's look at ways to enhance it to make it more robust and user-friendly.

Error Handling

One crucial improvement is adding error handling. For example, we should check if the user tries to divide by zero.

#include <iostream>
using namespace std;
int main()
{
 char ch;
 int A;
 int B;
 cout << "Enter operator (+, -, *, /, %): ";
 cin >> ch;
 cout << "Enter first number: ";
 cin >> A;
 cout << "Enter second number: ";
 cin >> B;
 switch (ch)
 {
 case '+':
 cout << "Result: " << A + B << endl;
 break;
 case '-':
 cout << "Result: " << A - B << endl;
 break;
 case '*':
 cout << "Result: " << A * B << endl;
 break;
 case '/':
 if (B == 0)
 {
 cout << "Error: Division by zero!" << endl;
 }
 else
 {
 cout << "Result: " << A / B << endl;
 }
 break;
 case '%':
 if (B == 0)
 {
 cout << "Error: Modulus by zero!" << endl;
 }
 else
 {
 cout << "Result: " << A % B << endl;
 }
 break;
 default:
 cout << "Invalid operation" << endl;
 }
 return 0;
}

In this enhanced version, we added checks for division by zero in both the division and modulus cases. If the user tries to divide by zero, an error message is displayed.

User Input Validation

Another improvement is validating user input to ensure they enter valid numbers and operators. This can be done using loops and conditional statements.

#include <iostream>
using namespace std;
int main()
{
 char ch;
 int A, B;
 bool validInput = false;
 while (!validInput)
 {
 cout << "Enter operator (+, -, *, /, %): ";
 cin >> ch;
 if (ch == '+' || ch == '-' || ch == '*' || ch == '/' || ch == '%')
 {
 validInput = true;
 }
 else
 {
 cout << "Invalid operator. Please enter +, -, *, /, or %." << endl;
 }
 }
 cout << "Enter first number: ";
 cin >> A;
 cout << "Enter second number: ";
 cin >> B;
 switch (ch)
 {
 case '+':
 cout << "Result: " << A + B << endl;
 break;
 case '-':
 cout << "Result: " << A - B << endl;
 break;
 case '*':
 cout << "Result: " << A * B << endl;
 break;
 case '/':
 if (B == 0)
 {
 cout << "Error: Division by zero!" << endl;
 }
 else
 {
 cout << "Result: " << A / B << endl;
 }
 break;
 case '%':
 if (B == 0)
 {
 cout << "Error: Modulus by zero!" << endl;
 }
 else
 {
 cout << "Result: " << A % B << endl;
 }
 break;
 }
 return 0;
}

Here, we use a while loop to continuously prompt the user for an operator until a valid one is entered. This ensures that the program doesn't proceed with an invalid operator.

Using Functions

To make the code more modular and readable, we can create separate functions for each operation.

#include <iostream>
using namespace std;
int add(int a, int b)
{
 return a + b;
}
int subtract(int a, int b)
{
 return a - b;
}
int multiply(int a, int b)
{
 return a * b;
}
double divide(int a, int b)
{
 if (b == 0)
 {
 cout << "Error: Division by zero!" << endl;
 return 0;
 }
 return (double)a / b;
}
int modulus(int a, int b)
{
 if (b == 0)
 {
 cout << "Error: Modulus by zero!" << endl;
 return 0;
 }
 return a % b;
}
int main()
{
 char ch;
 int A, B;
 cout << "Enter operator (+, -, *, /, %): ";
 cin >> ch;
 cout << "Enter first number: ";
 cin >> A;
 cout << "Enter second number: ";
 cin >> B;
 switch (ch)
 {
 case '+':
 cout << "Result: " << add(A, B) << endl;
 break;
 case '-':
 cout << "Result: " << subtract(A, B) << endl;
 break;
 case '*':
 cout << "Result: " << multiply(A, B) << endl;
 break;
 case '/':
 cout << "Result: " << divide(A, B) << endl;
 break;
 case '%':
 cout << "Result: " << modulus(A, B) << endl;
 break;
 default:
 cout << "Invalid operation" << endl;
 }
 return 0;
}

In this version, each arithmetic operation is performed by a separate function, making the code cleaner and easier to maintain.

Conclusion

Creating a switch-based calculator in C++ is a fantastic way to learn about control flow, input/output operations, and basic error handling. By enhancing the calculator with error checks, input validation, and modular functions, we can create a more robust and user-friendly application. I hope this guide helps you in your C++ journey. Keep coding, and have fun!