Summary:
A robust, console-based arithmetic engine designed to perform fundamental mathematical operations while maintaining high data integrity. This project serves as a foundational exercise in implementing the Model-View-Controller (MVC) pattern within a procedural-object-oriented hybrid structure, specifically optimized for the MinGW/GCC toolchain.
Learning Objectives:
Encapsulation: Implementing a logic class to separate mathematical operations from I/O.
Input Validation: Mastering the use of std::cin.clear() and std::cin.ignore() to prevent infinite loops on invalid data.
Stream Formatting: Using <iomanip> for professional decimal precision in scientific outputs.
The Source Code
This code is optimized for Code::Blocks. It includes necessary headers for buffer management and precision control.
#include <iostream>
#include <limits> // Required for clearing input buffers
#include <iomanip> // Required for setprecision
using namespace std;
// Logic Layer: The Calculator Class
class Calculator {
public:
double add(double a, double b) { return a + b; }
double subtract(double a, double b) { return a - b; }
double multiply(double a, double b) { return a * b; }
double divide(double a, double b) {
if (b == 0) throw "Division by zero error!";
return a / b;
}
};
// Interface Layer: Utility functions
void clearBuffer() {
cin.clear();
cin.ignore(numeric_limits<streamsize>::max(), '\n');
}
int main() {
Calculator calc;
int choice;
double num1, num2;
cout << fixed << setprecision(2); // Set global precision to 2 decimal places
while (true) {
cout << "\n===============================" << endl;
cout << " PRECISION CALC-ARCHITECT " << endl;
cout << "===============================" << endl;
cout << "1. Addition (+)\n2. Subtraction (-)\n3. Multiplication (*)\n4. Division (/)\n5. Exit" << endl;
cout << "Enter choice: ";
if (!(cin >> choice)) {
cout << "Invalid input! Please enter a number (1-5)." << endl;
clearBuffer();
continue;
}
if (choice == 5) break;
if (choice < 1 || choice > 5) {
cout << "Out of range! Select 1-5." << endl;
continue;
}
cout << "Enter first number: ";
while (!(cin >> num1)) {
cout << "Error: Enter a valid number: ";
clearBuffer();
}
cout << "Enter second number: ";
while (!(cin >> num2)) {
cout << "Error: Enter a valid number: ";
clearBuffer();
}
try {
switch (choice) {
case 1: cout << "Result: " << calc.add(num1, num2) << endl; break;
case 2: cout << "Result: " << calc.subtract(num1, num2) << endl; break;
case 3: cout << "Result: " << calc.multiply(num1, num2) << endl; break;
case 4: cout << "Result: " << calc.divide(num1, num2) << endl; break;
}
} catch (const char* msg) {
cerr << "MATH ERROR: " << msg << endl;
}
}
cout << "Program terminated safely." << endl;
return 0;
} |
Execution Trace (Sample Session)
===============================
PRECISION CALC-ARCHITECT
===============================
1. Addition (+)
2. Subtraction (-)
3. Multiplication (*)
4. Division (/)
5. Exit
Enter choice: 1
[HAPPY PATH]
Enter first number: 12.5
Enter second number: 7.25
Result: 19.75 |
===============================
Enter choice: 4
[ERROR HANDLING - MATH]
Enter first number: 10
Enter second number: 0
MATH ERROR: Division by zero error! |
===============================
Enter choice: ABC
[ERROR HANDLING - INPUT]
Invalid input! Please enter a number (1-5).
Academic "Learning Corner"
1. The MinGW "Buffer Problem"
In many IDEs like Code::Blocks, if a user enters a character (like 'A') into an integer variable, the std::cin stream enters a fail state. Subsequent calls to cin will be ignored, often resulting in an infinite loop. We solve this using:
2. Precision Formatting
By using std::fixed and std::setprecision(2), we ensure the output looks like a professional financial or scientific tool (e.g., 5.00 instead of 5), which is critical for user experience in technical software.
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...till the next post, bye-bye & take care
