Basic Input Output

C++ Output

In C++, cout  sends formatted output to standard output devices, such as the screen. We use the cout  object along with the << operator for displaying output.

Example

#include <iostream>

using namespace std;

int main() {

    // prints the string enclosed in double quotes

    cout << "This is C++ Programming";

    return 0;

}

 

Output

This is C++ Programming

 

How does this program work?

• We first include the iostream header file that allows us to display output.
• The cout object is defined inside the std namespace. To use the std namespace, we used the using namespace std; statement.
• Every C++ program starts with the main() function. The code execution begins from the start of the main() function.
• cout is an object that prints the string inside quotation marks " ". It is followed by the << operator.
• return 0; is the "exit status" of the main() function. The program ends with this statement, however, this statement is not mandatory.

Note: If we don't include the using namespace std; statement, we need to use std :: cout  instead of cout.

 

Example

To print the numbers and character variables, we use the same  cout object but without using quotation marks.

#include <iostream>

using namespace std;

int main() {

    int num1 = 70;

    double num2 = 256.783;

    char ch = 'A';

    cout << num1 << endl;    // print integer

    cout << num2 << endl;    // print double

    cout << "character: " << ch << endl;    // print char

    return 0;

}

Output

70

 256.783

 character: A

Notes:

The endl manipulator is used to insert a new line. That's why each output is displayed in a new line.

 

C++ Input

In C++, cin takes formatted input from standard input devices such as the keyboard. We use the cin object along with the >> operator for taking input.

Example

#include <iostream>

using namespace std;

int main() {

    int num;

    cout << "Enter an integer: ";

    cin >> num;   // Taking input

    cout << "The number is: " << num;

    return 0;

}

 

Output

Enter an integer: 70

 The number is: 70

 

In the program, we used

cin >> num;

 

to take input from the user. The input is stored in the variable num. We use the >> operator with cin to take input.