🟢 Foundation · Lesson 10

Type Conversion and Type Casting

What is Type Conversion and Type Casting?

Type Conversion and Type Casting
Type conversion changes a value from one data type to another. It may be automatic or explicit. Correct casting is important in division, average and percentage calculations.

Level
🟢 Beginner – C++ Foundation

Example File
type-casting.cpp

Main Focus
Concept + syntax + practical C++ program

Why should you learn this?

It helps you write correct and readable C++ programs.
It is used repeatedly in school practicals, projects and competitive programming.
It builds the base for advanced topics such as OOP, STL and data structures.

Important Terms

Term	Meaning / Use
implicit conversion	Type Conversion and Type Casting programming में Implicit conversion use होता है।
explicit casting	Type Conversion and Type Casting programming में Explicit casting use होता है।
static_cast	Type Conversion and Type Casting programming में Static_cast use होता है।
promotion	Type Conversion and Type Casting programming में Promotion use होता है।

Syntax / Pattern

C++

static_cast<type>(value)

Example Program

main.cpp

#include <iostream>
using namespace std;

int main() {
    int total = 455;
    int subjects = 5;
    double percentage = static_cast<double>(total) / subjects;
    cout << percentage;
    return 0;
}

Expected Output

Program Explanation

Without casting, integer division may remove decimal part.
static_cast<double> converts total into decimal type before division.

Exam Tip: In C++ practical answers, write the logic first, then the program, then expected output. For theory, always include one suitable example.

Where will you use it?

percentage calculation
average marks
currency conversion

Common Mistakes

Expecting 5/2 to give 2.5 in integer division.
Using unsafe casts unnecessarily.

Practice Tasks

Find average of 3 integers as decimal.
Explain implicit and explicit conversion.

Summary

Type Conversion and Type Casting एक ज़रूरी C++ topic है। परिभाषा सीखें, syntax समझें, example program चलाएं और फिर practice tasks हल करके concept मज़बूत करें।