C++ If Statement

C++ provides several conditional statements that allow programs to make decisions based on logical evaluations. These conditions guide the execution of different blocks of code.

Using Conditions for Decision-Making

Programs often need to react to different situations. C++ supports logical conditions such as:

• if → Runs a block only if the specified condition is true.
• else → Runs a block if the if condition is false.
• else if → Introduces additional conditions when the first condition fails.
• switch → Evaluates a variable and selects a matching case.

For this lesson, we’ll focus only on the if statement.

Comparison Operators for Conditions

These operators help check relationships between values:

These operators define logical conditions used in if statements.

Using if to Execute Code Conditionally

An if statement ensures that a specific block of code runs only if a condition evaluates to true.

Syntax

if (condition) {
    // Code executes only if condition is true
}

if (condition) {

    // Code executes only if condition is true

}

​

Important: C++ is case-sensitive! Writing If or IF instead of if will cause an error.

Example: Simple if Statement

The program below checks if 250 is greater than 200. Since the condition is true, the message will be displayed.

#include <iostream>
using namespace std;

int main() {
    if (250 > 200) {
        cout << "250cc engines have more power than 200cc ones.";
    }

    return 0;
}

#include <iostream>

using namespace std;

​

int main() {

    if (250 > 200) {

        cout << "250cc engines have more power than 200cc ones.";

    }

​

    return 0;

}

​

Using Variables in an if Statement

Instead of comparing fixed numbers, you can use variables.

Example

#include <iostream>
using namespace std;

int main() {
    int horsepower1 = 500;
    int horsepower2 = 450;

    if (horsepower1 > horsepower2) {
        cout << "The first car has more horsepower.";
    }

    return 0;
}

#include <iostream>

using namespace std;

​

int main() {

    int horsepower1 = 500;

    int horsepower2 = 450;

​

    if (horsepower1 > horsepower2) {

        cout << "The first car has more horsepower.";

    }

​

    return 0;

}

​

Explanation:

• horsepower1 is 500.
• horsepower2 is 450.
• Since 500 is greater than 450, the program prints:
  “The first car has more horsepower.”