C++ Input and Output

So far, we have displayed fixed values using cout. But real programs often need to take information from the user.

For example, a program may ask for your name, age, or marks and then display the information.

C++ mainly uses:

• cout to display output
• cin to take input

Display Output Using cout

We use cout to display text or values on the screen.

#include <iostream>
using namespace std;

int main() {
    cout << "Welcome to C++!";

    return 0;
}

Output:

Welcome to C++!

You can also display a variable:

#include <iostream>
using namespace std;

int main() {
    int age = 14;

    cout << "Age: " << age;

    return 0;
}

Output:

Age: 14

Take Input Using cin

cin is used to take input from the user.

For example:

#include <iostream>
using namespace std;

int main() {
    int age;

    cout << "Enter your age: ";
    cin >> age;

    cout << "Your age is: " << age;

    return 0;
}

If the user enters:

14

The output will be:

Enter your age: 14
Your age is: 14

Here:

cin >> age;

takes the value entered by the user and stores it in the age variable.

Taking Different Types of Input

You can use cin with different data types.

#include <iostream>
using namespace std;

int main() {
    int age;
    double marks;

    cout << "Enter your age: ";
    cin >> age;

    cout << "Enter your marks: ";
    cin >> marks;

    cout << "Age: " << age << "\n";
    cout << "Marks: " << marks;

    return 0;
}

Example input:

14
88.5

Output:

Age: 14
Marks: 88.5

Taking Multiple Inputs

You can take multiple values using one cin statement.

#include <iostream>
using namespace std;

int main() {
    int age;
    int marks;

    cout << "Enter age and marks: ";
    cin >> age >> marks;

    cout << "Age: " << age << "\n";
    cout << "Marks: " << marks;

    return 0;
}

The user can enter:

14 90

Output:

Age: 14
Marks: 90

Taking String Input

You can use cin to take a single word as input.

#include <iostream>
#include <string>
using namespace std;

int main() {
    string name;

    cout << "Enter your name: ";
    cin >> name;

    cout << "Hello, " << name;

    return 0;
}

If the user enters:

Rahul

The output will be:

Hello, Rahul

However, cin stops reading when it finds a space.

For example, if the user enters:

Rahul Kumar

only Rahul will be stored.

Using getline()

To take a complete line of text, including spaces, use getline().

#include <iostream>
#include <string>
using namespace std;

int main() {
    string name;

    cout << "Enter your full name: ";
    getline(cin, name);

    cout << "Hello, " << name;

    return 0;
}

If the user enters:

Rahul Kumar

Output:

Hello, Rahul Kumar

Moving to a New Line

You can use \n to move the output to a new line.

#include <iostream>
using namespace std;

int main() {
    cout << "Hello\n";
    cout << "Welcome to C++";

    return 0;
}

Output:

Hello
Welcome to C++

You can also use endl:

cout << "Hello" << endl;
cout << "Welcome to C++";

Both \n and endl can be used to move to the next line.

A Simple Input and Output Program

Let’s create a small program that asks for a student’s name and age.

#include <iostream>
#include <string>
using namespace std;

int main() {
    string name;
    int age;

    cout << "Enter your name: ";
    getline(cin, name);

    cout << "Enter your age: ";
    cin >> age;

    cout << "\nName: " << name;
    cout << "\nAge: " << age;

    return 0;
}

Example input:

Enter your name: Anjali
Enter your age: 14

Output:

Name: Anjali
Age: 14

Key Points to Remember

• cout is used to display output.
• cin is used to take input.
• >> is used with cin to read values.
• getline() can read a complete line of text.
• \n moves the output to a new line.
• endl also moves the output to a new line.
• cin can be used with different data types.

What’s Next?

Now that you know how to take input and display output, the next chapter will introduce C++ Operators and show you how to perform calculations and comparisons in your programs.

Frequently Asked Questions (FAQs)

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

Nidhi Srivastav