🟢 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	Implicit conversion used in Type Conversion and Type Casting programming.
explicit casting	Explicit casting used in Type Conversion and Type Casting programming.
static_cast	Static_cast used in Type Conversion and Type Casting programming.
promotion	Promotion used in Type Conversion and Type Casting programming.

Syntax / Pattern

static_cast<type>(value)

Example Program

#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 is an important C++ topic. Learn the definition, understand the syntax, run the example program and then solve the practice tasks to make the concept strong.