Summary  
This chapter demonstrates how to use conditional branching and boolean comparisons to evaluate three numeric inputs and print the type of triangle they form.

General domain of usage  
Geometry processing

#define CATCH_CONFIG_MAIN
#include <catch2/catch.hpp>
#include <iostream>
#include <sstream>

// Function declaration
double performOperation(int operationType, double a, double b);

// ------------------- Tests -------------------

TEST_CASE("Addition: performOperation(1, 5, 3) => 8 and prints 'Adding numbers'", "[performOperation]") {
    std::ostringstream oss;
    std::streambuf* oldCout = std::cout.rdbuf(oss.rdbuf());

    double result = performOperation(1, 5.0, 3.0);

    std::cout.rdbuf(oldCout); // restore original buffer

    REQUIRE(result == Approx(8.0));
}

TEST_CASE("Subtraction: performOperation(2, 10, 4) => 6 and prints 'Subtracting numbers'", "[performOperation]") {
    std::ostringstream oss;
    std::streambuf* oldCout = std::cout.rdbuf(oss.rdbuf());

    double result = performOperation(2, 10.0, 4.0);

    std::cout.rdbuf(oldCout);

    REQUIRE(result == Approx(6.0));
}

TEST_CASE("Multiplication: performOperation(3, 6, 7) => 42 and prints 'Multiplying numbers'", "[performOperation]") {
    std::ostringstream oss;
    std::streambuf* oldCout = std::cout.rdbuf(oss.rdbuf());

    double result = performOperation(3, 6.0, 7.0);

    std::cout.rdbuf(oldCout);

    REQUIRE(result == Approx(42.0));
}

TEST_CASE("Division: performOperation(4, 20, 4) => 5 and prints 'Dividing numbers'", "[performOperation]") {
    std::ostringstream oss;
    std::streambuf* oldCout = std::cout.rdbuf(oss.rdbuf());

    double result = performOperation(4, 20.0, 4.0);

    std::cout.rdbuf(oldCout);

    REQUIRE(result == Approx(5.0));
}

TEST_CASE("Division by zero: performOperation(4, 10, 0) => 0 and prints error", "[performOperation]") {
    std::ostringstream oss;
    std::streambuf* oldCout = std::cout.rdbuf(oss.rdbuf());

    double result = performOperation(4, 10.0, 0.0);

    std::cout.rdbuf(oldCout);

    REQUIRE(result == Approx(0.0));
    REQUIRE(oss.str().find("Error: Division by zero") != std::string::npos);
}

TEST_CASE("Unknown operation: performOperation(99, 5, 5) => 0 and prints unknown operation", "[performOperation]") {
    std::ostringstream oss;
    std::streambuf* oldCout = std::cout.rdbuf(oss.rdbuf());

    double result = performOperation(99, 5.0, 5.0);

    std::cout.rdbuf(oldCout);

    REQUIRE(result == Approx(0.0));
    REQUIRE(oss.str().find("Invalid operation type") != std::string::npos);
}

test.cpp

Welcome to a beginner-friendly course that will help you learn the core concepts of conditional statements . Whether you're new to programming or looking to improve your understanding of conditional statements and how they influence the flow of your programs, this course is designed to meet your needs.

This is your gateway to understanding the fundamental building blocks of decision making. Gain the essential knowledge to make your programs more intelligent and responsive.

Apply and reinforce your knowledge of conditional flow control concepts. You will be presented with a series of engaging programming challenges to test and expand your knowledge.

Take your skills to the next level by exploring and learning advanced features and techniques to deepen your understanding and strengthen your knowledge.

Challenge: Math Operation Handler

Solution