Compound Statements in C++

Compound statements in C++ are blocks used to group multiple statements together into a single unit. These statements are enclosed in curly braces {} and can be used wherever a single statement is expected. The statements put inside curly braces are executed just like a single statement would have been executed. The compound statements help in organizing code and provide a way to execute multiple statements sequentially.

Syntax of Compound Statements

The compound statements look like this in the program:

{
    // Statements
    statement1;
    statement2;
    // ...
    statementN;
}

We just have to put multiple statements in the braces {}.

Examples of Compound Statements

Example 1: Using Compound Statements with Functions

The compound statements are commonly used within the function definitions. All the statements inside a function’s body are enclosed as the compound statement.

C++

// C++ Program to illustrate Compound Statements in
// Functions
#include <iostream>
using namespace std;

void GFG()
// compound statement start
{
    cout << "Hello World" << endl;
}
// compound statement end

// driver code
int main()
{
    GFG();
    return 0;
}

Output

1 2 3 4 5 

Example 2: Compound Statement with if Statement

The compound statements are used in if statements for the instance when multiple statements need to be executed conditionally.

C++

// C++ Program to illustrate Compound Statements in
// Conditional Statements
#include <iostream>
using namespace std;

int main()
{
    int x = 20;
    if (x > 6) {
        cout << "x is greater than 6"
             << std::endl; // statement 1
        cout << "Inside the if block"
             << std::endl; // statement 2
    }
    return 0;
}

Output

x is greater than 6
Inside the if block

Example 3: Simple Compound Statement Inside a Function

In this program, we will use we’ll use a compound statement in between a function which also controls the scope of the variables.

C++

// C++ Program to illustrate Compound Statements in Variable
// Scope
#include <iostream>
using namespace std;

int main()
{
    int x = 8; // Outer variable
    cout << "Outer x: " << x << endl;

    // Variable Scope Starts
    {
        int x = 30;
        cout << "Inner x: " << x << endl;
    }
    // Variable Scope Ends

    // Access the outer x after the inner block scope
    cout << "Outer x: " << x << endl;

    return 0;
}

Output

Outer x: 8
Inner x: 30
Outer x: 8

Conclusion

As we have seen, compound statements are an integral part of the C programming languages. It is used with almost all of the components of the C to group the statements together or provide a separate scope.