Temperature Converter in C++ Last Updated : 19 Jul, 2025 Comments Improve Suggest changes Like Article Like Report In this project, you will build a simple command-line application that allows users to convert temperatures between Celsius and Fahrenheit. The program should take the user’s choice, perform the appropriate conversion, and display the result. It should continue running based on the user's input and handle invalid choices appropriately, as described in the features below.FeaturesOur temperature converter program will have the following features:Convert Celsius to FahrenheitConvert Fahrenheit to CelsiusValidate user input for menu selectionKeep running until the user chooses to exitExample: C++ Temperature Converter 1. Celsius to Fahrenheit 2. Fahrenheit to Celsius 3. Exit Enter your choice (1-3): 1 Enter temperature in Celsius: 25 25 C = 77 F Temperature Converter 1. Celsius to Fahrenheit 2. Fahrenheit to Celsius 3. Exit Enter your choice (1-3): 2 Enter temperature in Fahrenheit: 98.6 98.6 F = 37 C Temperature Converter 1. Celsius to Fahrenheit 2. Fahrenheit to Celsius 3. Exit Enter your choice (1-3): 4 Invalid choice. Please try again. Temperature Converter 1. Celsius to Fahrenheit 2. Fahrenheit to Celsius 3. Exit Enter your choice (1-3): 3 Exiting temperature converter. Try to solve this yourself before looking at the solution below.Project RequirementsYou must be familiar with the following topics in C++:Variable, Data Types and ConstantsBasic input/outputOperatorsDecision Making and LoopsImplementationWe start by defining constexpr constants for the conversion factors.Then, we use a while (true) loop to keep the converter running. Inside the loop, we display a menu and take user input. Based on the input, the appropriate conversion is performed. Input is validated to handle invalid menu choices. C++ #include <iostream> using namespace std; // Define conversion constants const double celToFahMult = 9.0 / 5.0; const double fahToCelMult = 5.0 / 9.0; const int fahOffset = 32; int main() { int choice; double temp, converted; // Repeat until user chooses to exit while (true) { // Display menu cout << "\nTemperature Converter\n"; cout << "1. Celsius to Fahrenheit\n"; cout << "2. Fahrenheit to Celsius\n"; cout << "3. Exit\n"; cout << "Enter your choice (1-3): "; cin >> choice; // Exit condition if (choice == 3) { cout << "Exiting temperature converter.\n"; break; } // Celsius to Fahrenheit if (choice == 1) { cout << "Enter temperature in Celsius: "; cin >> temp; converted = (temp * celToFahMult) + fahOffset; cout << temp << " C = " << converted << " F\n"; } // Fahrenheit to Celsius else if (choice == 2) { cout << "Enter temperature in Fahrenheit: "; cin >> temp; converted = (temp - fahOffset) * fahToCelMult; cout << temp << " F = " << converted << " C\n"; } // Invalid choice else { cout << "Invalid choice. Please try again.\n"; } } return 0; } ExecutionWhen you compile and run the program, it displays:SummaryIn this project, we learned:How to create a simple temperature converter using cin and coutHow to use constexpr to define conversion factorsHow to use conditional statements to handle menu choicesHow to use a while loop to allow multiple conversions until exitYou can also extend this program to support kelvin (K) also. Comment More infoAdvertise with us Next Article Introduction to C++ Programming Language A abhishekcpp Follow Improve Article Tags : C++ C++ Projects Practice Tags : CPP Similar Reads C++ Programming Language C++ is a computer programming language developed by Bjarne Stroustrup as an extension of the C language. It is known for is fast speed, low level memory management and is often taught as first programming language. It provides:Hands-on application of different programming concepts.Similar syntax to 5 min read C++ OverviewIntroduction to C++ Programming LanguageC++ is a general-purpose programming language that was developed by Bjarne Stroustrup as an enhancement of the C language to add object-oriented paradigm. It is considered as a middle-level language as it combines features of both high-level and low-level languages. It has high level language featur 3 min read Features of C++C++ is a general-purpose programming language that was developed as an enhancement of the C language to include an object-oriented paradigm. It is an imperative and compiled language. C++ has a number of features, including:Object-Oriented ProgrammingMachine IndependentSimpleHigh-Level LanguagePopul 5 min read History of C++The C++ language is an object-oriented programming language & is a combination of both low-level & high-level language - a Middle-Level Language. 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These two ways are generally differentiated by the type of values passed to them as parameters.The following table lists the differences between the call-by-value and call-by-reference methods of parameter passing.Call By Valu 4 min read Default Arguments in C++A default argument is a value provided for a parameter in a function declaration that is automatically assigned by the compiler if no value is provided for those parameters in function call. If the value is passed for it, the default value is overwritten by the passed value.Example:C++#include <i 5 min read Inline Functions in C++In C++, inline functions provide a way to optimize the performance of the program by reducing the overhead related to a function call. 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In this article, we will discuss some of the major applications of pointers in C. Prerequisite: Pointers in C. C Pointers Appl 4 min read Understanding nullptr in C++Consider the following C++ program that shows problem with NULL (need of nullptr) CPP // C++ program to demonstrate problem with NULL #include <bits/stdc++.h> using namespace std; // function with integer argument void fun(int N) { cout << "fun(int)"; return;} // Overloaded fun 3 min read References in C++In C++, a reference works as an alias for an existing variable, providing an alternative name for it and allowing you to work with the original data directly.Example:C++#include <iostream> using namespace std; int main() { int x = 10; // ref is a reference to x. int& ref = x; // printing v 5 min read Can References Refer to Invalid Location in C++?Reference Variables: You can create a second name for a variable in C++, which you can use to read or edit the original data contained in that variable. 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