Cout : Display Output to User in C++ (Insertion Operator in C++)

Cout : Display Output to User Using Screen(Monitor)

In C++ Insertion operator is used to display value to the user. The value may be some message in the form of string or variable.

Syntax : Display Value to User

cout << variable;

Explanation : Insertion Operator

Include <iostream.h> header file to use cin.

#include<iostream.h>//traditional C++
OR
#include<iostream>// ANSI Standard
using namespace std;

cout is used for displaying data on the screen.
The operator << called as insertion operator or put to operator.
The Insertion operator can be overloaded.
Insertion operator is similar to the printf() operation in C.
cout is the object of ostream class.
Data flow direction is from variable to output device.
We can still use printf() for displaying an output..
Multiple outputs can be displayed using cout.

Live Example : Displaying Output on Screen

#include<iostream.h>
using namespace std;
int main()
{
    int number1;
    int number2;
    cout<<"Enter First Number: ";
    /* Display the message to tell the 
          user to do appropriate action */
    cin>>number1;
    cout<<"Enter Second Number: ";
    /* Display the message to tell the 
          user to do appropriate action */
    cin>>number1;
    cin>>number2;
    cout<<"Addition : ";
    cout<<number1+number2;  //Display Result
    return 0;
}

Output :

Enter First Number: 8
Enter Second Number: 8
Addition : 16

Different ways of using cout in c++

Way 1. Simple Use of cout and Insertion Operator:

int tempNumber=6;
cout << tempNumber;

In above example, tempNumber is declared as integer variable. And value 6 is assigned to it.
when control comes over cout , Program will display the output to screen.
Likewise we can display integer, character or string.

Way 2 : Cascading Multiple Variables in Cout

int a=10;
int b=20;
cout << a << b;

is similar to -

int a=10;
int b=20;
cout << a;
cout << b;

Way 3 : cout to display string

cout << string ; //for displaying string output
or
cout << "Display String" ;

The extraction operator is also used for getting string.
When blank space is detected, extraction operator stops reading input.
cin allow us to enter only one word.
For reading entire line, we use getline() function.

Way 4 : Use of expression in cout

int num1;
int num2;
cin >> num1;
cin >> num2;
cout<< "Addition is : " << num1+num2 ;

Expression can be evaluated inside cout statement.
In above example, we are accepting 2 values from user.
The addition of two numbers is displayed on the screen
For that we use the expression for adding two numbers in the output statement directly.

Way 5 : Display Output on new line

We can use ‘n‘ or ‘endl‘ to print the output on new line.

cout << "Hello,n";
cout << "My name is nPooja...";
or
cout << "Hello," <<endl;
cout << "My name is" <<endl;
cout << "Pooja..." <<endl;

Output :

Hello,
My name is
Pooja...

*External Link : More on cout | cout Statement | Sample Example