C++ true Keyword

The true keyword in C++ represents the Boolean value true. It is used in logical and conditional expressions to indicate a condition that evaluates to true. Along with false, it is part of the bool data type, which was introduced in C++ as part of the Standard Library.

The value of true is equivalent to 1 when used in arithmetic expressions or converted to an integer type. It plays a key role in control flow statements such as if, while, and for.

Syntax

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bool variable = true;
true
A Boolean constant representing the logical value “true.”

Examples

Example 1: Basic Usage of true

In this example, you will learn the use of true in a Boolean variable and a conditional statement.

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#include <iostream>
using namespace std;

int main() {
    bool isRunning = true;

    if (isRunning) {
        cout << "The program is running." << endl;
    }

    return 0;
}

Output:

The program is running.

Explanation:

  1. The Boolean variable isRunning is assigned the value true.
  2. The if statement checks if isRunning evaluates to true, and the corresponding block executes.
  3. The message is printed because the condition evaluates to true.

Example 2: Using true in Loops

The true keyword can be used to create infinite loops, which can be exited with a break statement.

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#include <iostream>
using namespace std;

int main() {
    int count = 0;

    while (true) {
        cout << "Count: " << count << endl;
        count++;

        if (count == 5) {
            break; // Exit the loop
        }
    }

    return 0;
}

Output:

Count: 0
Count: 1
Count: 2
Count: 3
Count: 4

Explanation:

  1. The while (true) loop runs indefinitely because the condition always evaluates to true.
  2. Inside the loop, the value of count is incremented and printed.
  3. The break statement exits the loop when count reaches 5.

Example 3: Using true with Logical Expressions

The true keyword can be combined with logical operators in conditional expressions.

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#include <iostream>
using namespace std;

int main() {
    bool isConnected = true;
    bool isAuthenticated = false;

    if (isConnected && !isAuthenticated) {
        cout << "User is connected but not authenticated." << endl;
    }

    return 0;
}

Output:

User is connected but not authenticated.

Explanation:

  1. The variable isConnected is true, and isAuthenticated is false.
  2. The logical expression isConnected && !isAuthenticated evaluates to true, so the if block executes.
  3. The message is printed to indicate the user’s state.

Key Points to Remember about true Keyword

  • The true keyword represents the Boolean value for “true.”
  • It is part of the bool data type and is equivalent to 1 in arithmetic expressions.
  • It is commonly used in control flow statements like if, while, and for.
  • In infinite loops, true can be used as the condition to ensure continuous execution until explicitly broken.
  • Using true makes code more readable and aligns with C++’s type-safe practices.