C++ Basic Input/Output
C++ Basic Input/Output
In this tutorial, we will learn to use the cin object to take input from the user, and the cout object to display output to the user with the help of examples.
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 1: String Output
#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
iostreamheader file that allows us to display output. - The
coutobject is defined inside thestdnamespace. To use thestdnamespace, we used theusing namespace std;statement. - Every C++ program starts with the
main()function. The code execution begins from the start of themain()function. coutis an object that prints the string inside quotation marks" ". It is followed by the<<operator.return 0;is the "exit status" of themain()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.
This is the preferred method as using the std namespace can create potential problems.
However, we have used the std namespace in our tutorials in order to make the codes more readable.
#include <iostream>
int main() {
// prints the string enclosed in double quotes
std::cout << "This is C++ Programming";
return 0;
}
Example 2: Numbers and Characters Output
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
endlmanipulator is used to insert a new line. That's why each output is displayed in a new line. - The
<<operator can be used more than once if we want to print different variables, strings and so on in a single statement. For example:
cout << "character: " << ch << endl;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 3: Integer Input/Output
#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.
Note: If we don't include the using namespace std; statement, we need to use std::cin instead of cin.
C++ Taking Multiple Inputs
#include <iostream>
using namespace std;
int main() {
char a;
int num;
cout << "Enter a character and an integer: ";
cin >> a >> num;
cout << "Character: " << a << endl;
cout << "Number: " << num;
return 0;
}
Output
Enter a character and an integer: F 23 Character: F Number: 23 :
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