---
title: 3.13 Increment and Decrement Operators
description: "The increment (`++`) and decrement (`--`) operators are unary operators used to increase or decrease the value of a variable by one. These operators are commonly used in loops, counters, and array indexing. Both operators are available in two forms:…"
url: "https://edcret.in/docs/cpp-programming/operators-cplusplus/3-13-increment-and-decrement-operators/"
updated: "2026-07-28"
category: C++ Programming / Operators
---

# 3.13 Increment and Decrement Operators

The increment (`++`) and decrement (`--`) operators are unary operators used to increase or decrease the value of a variable by one. These operators are commonly used in loops, counters, and array indexing.

Both operators are available in two forms: **prefix** and **postfix**. The prefix form modifies the variable before its value is used, whereas the postfix form uses the current value first and then updates the variable.

## Source Code

```
#include <iostream>

int main()
{
    int value = 10;

    std::cout << "Initial Value : " << value << 'n';

    std::cout << "Prefix Increment  (++value): " << ++value << 'n';
    std::cout << "Postfix Increment (value++): " << value++ << 'n';
    std::cout << "Value After Postfix         : " << value << 'n';

    std::cout << "Prefix Decrement  (--value): " << --value << 'n';
    std::cout << "Postfix Decrement (value--): " << value-- << 'n';
    std::cout << "Value After Postfix         : " << value << 'n';

    return 0;
}
```

## Output

```
Initial Value : 10
Prefix Increment  (++value): 11
Postfix Increment (value++): 11
Value After Postfix         : 12
Prefix Decrement  (--value): 11
Postfix Decrement (value--): 11
Value After Postfix         : 10
```

## Explanation

- The increment operator (`++`) increases the value of a variable by one.
- The decrement operator (`--`) decreases the value of a variable by one.
- The prefix increment operator (`++value`) increments the variable before its value is used in the expression.
- The postfix increment operator (`value++`) uses the current value first and increments the variable afterward.
- The prefix decrement operator (`--value`) decrements the variable before its value is used.
- The postfix decrement operator (`value--`) uses the current value first and decrements the variable afterward.
- Increment and decrement operators can only be applied to modifiable variables.
- `return 0;` terminates the program successfully.