C++ Conditional Statements

Programs often need to make decisions.

For example:

• If a student scores 40 or more, they pass.
• If someone’s age is 18 or more, they can vote.
• If a number is greater than 0, it is positive.

C++ conditional statements make these decisions possible.

The if Statement

The if statement runs a block of code when a condition is true.

Syntax

if (condition) {
    // code to run
}

For example:

#include <iostream>
using namespace std;

int main() {
    int age = 18;

    if (age >= 18) {
        cout << "You can vote.";
    }

    return 0;
}

Output:

You can vote.

Here, age >= 18 is true, so the message is displayed.

The if...else Statement

Sometimes you want one block of code to run when the condition is true and another block when it is false.

For this, use if...else.

#include <iostream>
using namespace std;

int main() {
    int age = 16;

    if (age >= 18) {
        cout << "You can vote.";
    } else {
        cout << "You cannot vote.";
    }

    return 0;
}

Output:

You cannot vote.

The else if Statement

When you need to check more than one condition, you can use else if.

For example, let’s check a student’s marks:

#include <iostream>
using namespace std;

int main() {
    int marks = 75;

    if (marks >= 90) {
        cout << "Grade A+";
    } else if (marks >= 75) {
        cout << "Grade A";
    } else if (marks >= 60) {
        cout << "Grade B";
    } else {
        cout << "Needs improvement";
    }

    return 0;
}

Output:

Grade A

C++ checks the conditions from top to bottom. Once it finds a true condition, it runs that block and skips the remaining conditions.

Nested if

An if statement can be placed inside another if statement. This is called a nested if.

#include <iostream>
using namespace std;

int main() {
    int age = 20;
    bool hasID = true;

    if (age >= 18) {
        if (hasID) {
            cout << "You can enter.";
        }
    }

    return 0;
}

Output:

You can enter.

Nested if statements are useful when one condition depends on another.

The switch Statement

The switch statement is useful when you want to choose between several fixed options.

For example:

#include <iostream>
using namespace std;

int main() {
    int day = 2;

    switch (day) {
        case 1:
            cout << "Monday";
            break;

        case 2:
            cout << "Tuesday";
            break;

        case 3:
            cout << "Wednesday";
            break;

        default:
            cout << "Invalid day";
    }

    return 0;
}

Output:

Tuesday

How switch Works

The value of day is 2, so C++ looks for:

case 2:

It finds the matching case and runs its code.

The break statement stops the switch after the matching case.

default runs when none of the cases match.

Ternary Operator

The ternary operator is a short way to write a simple if...else condition.

Syntax

condition ? valueIfTrue : valueIfFalse;

Example:

#include <iostream>
using namespace std;

int main() {
    int age = 20;

    string result = (age >= 18) ? "Adult" : "Minor";

    cout << result;

    return 0;
}

Output:

Adult

The ternary operator is useful for simple conditions, while if...else is usually easier to read for larger decisions.

A Simple Example

Let’s create a program that checks whether a number is positive, negative, or zero.

#include <iostream>
using namespace std;

int main() {
    int number = -5;

    if (number > 0) {
        cout << "Positive number";
    } else if (number < 0) {
        cout << "Negative number";
    } else {
        cout << "Zero";
    }

    return 0;
}

Output:

Negative number

Key Points to Remember

• Conditional statements help a program make decisions.
• if runs code when a condition is true.
• else runs when the if condition is false.
• else if checks additional conditions.
• A nested if contains one if statement inside another.
• switch is useful for choosing between fixed options.
• break stops a switch case.
• The ternary operator provides a short way to write simple if...else conditions.

What’s Next?

In the next chapter, we will learn about C++ Loops and see how to repeat a block of code without writing the same statements again and again.

Frequently Asked Questions (FAQs)

Written by Shubhranshu Shekhar, who has trained 20000+ students in coding.

Nidhi Srivastav