C++ Stream: Basic Input/output Stream objects in C++ with example codes

(Last Updated On: April 4, 2021)

Table of Contents

C++ stream Description:

C++ Stream Objects- In this article you will learn how to use cin stream object and cout stream object in C++ programming

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The Predefined C++ Stream Object:

Predefined C++ stream objects are used for basic input and output. A C++ stream refers to a flow of data. The data may flow from the input device into the main memory or from the main memory to the output device.

C++ provides various predefined C++ stream objects. The basic input/output C++ stream objects are cin, cout, cerr, and clog. The cin object is associated with standard input and cout object is associated with standard output. The cerr and clog both objects are linked to the standard output.

C++ input/output stream is declared in the header file “iostream.h”. in most of the c++ program, this header file( iostream.h) must be included for the input and output of data.


The ‘cin’ C++ Stream Object:

the word cin stands for console input. It is pronounced as “see in”. it is the standard input C++ stream object. It is used as an input statement to get input from user through keyword during the execution of the program. This C++ stream object represents the flow of data from input device ( i.e. keyword) to the computer memory. The cin stream input object is also part of iostream.h header file.

C++ Stream

When an input statement is executed, the computer waits to get input from the keyboard. When a value is typed and the enter key is pressed, the value is assigned to the variable, and control shifts to the next statement.

The syntax of cin is as follow:

Cin>>var1 [>>var2] [>>var3]……….;

Where

cin:

It is the name of the standard input C++ stream object.

>:

It is known as an extraction operator or get from the operator. It takes input from cin object and assigns it to the variable. We can use multiple extraction operators to get input into multiple variables.

var1,var2,var3……:

it indicates a list of variables separated by extraction operator (>>). There must be a variable on the right-side of each ‘>>’ operator in which the input value is stored.

Examples:

  • The following statement inputs a value from the keyboard and stores it in variable marks during the execution of the program:

cin>>marks;

 

  • The following statement gets three values and stores these values in variables x,y, and z respectively:

Cin>>x>>y>>z;

When this statement is executed, the user can enter the values by using one of the following ways:

  • Type value for the first variable and press the enter key. The computer will wait to get the value for the second variable. Repeat this process until values in all variables have been entered.

OR

  • Type the values of all variables separated by spaces and then press the enter key.



cin C++ Stream object Programming Examples:

Write a program that inputs a character and displays its ASCII code using cin cout stream objects:

Write a program that inputs time in seconds and converts it into a standard format (such as hh:mm:ss format) using cin cout stream objects:

A car can travel 5.3 miles in one liter. Write a program that inputs petrol in liters and displays how much distance the car can cover using the available petrol using cin, cout stream objects:


Example: write a program that inputs the name, age, height and gender of a student using ‘cin C++ stream  object’:

Flow chart:

C++ Stream

Programming:

C++ Stream

Example: write a program that inputs distance in miles from user and converts miles into kilometers. One mile =1.609 kilometer using cin cout stream objects:

C++ Stream

Example: write a program in C++ to converts pound into kilograms using cin cout stream objects:

1 pound = 0.453592

C++ Stream


Example: write a program in C++ which convert Inches to centimeters using cin cout stream objects:

1 inch = 2.54 centimeters

C++ Stream

Example: writes a program in C++ to calculate the volume and surface area of a sphere using cin cout stream objects:

Formula:

area of sphere = 4  R2

circumference f sphere = 4/3 R3

the value of  is = 3.1417

C++ Stream

Example: write a program in C++ which calculate the area and circumference of the circle using cin cout stream objects:

Formula:

area of circle = π R2
circumference of circle= 2 πR
the value of π is = 3.1417

Flowchart:

C++ Stream

Program:

C++ Stream


Example: write a temperature program in C++ which converts the Fahrenheit to Centigrade using cin cout stream objects:

C=5/9(F-32)

Flowchart:

C++ Stream

Program:

C++ Stream

Example: write a program that inputs marks obtained by a student in five different subjects and find out aggregate marks (total marks) and percentage using cin cout stream objects:

C++ Stream

Example: write a program that inputs the value of three sides of a triangle and finds out its area using cin cout stream objects:

Formula:

C++ Stream

C++ Stream



Example: write a program which consists of three variable Area, Perpendicular, and Base. The program inputs the values in variables per and base from the user and computes the area of a triangle using cin cout stream objects:

Formula:

Area = (base*per)/2

C++ Stream

Example: write a program in C++ which reverse the order of the long numbers using cin cout stream objects:

C++ Stream

Write a program that inputs the current price of gas and electricity per unit. Give each item’s rate with an increment of 20%. The program computes the new price of gas and electricity using cin cout stream objects:

C++ Stream


write a program which calculates the employee dearness allowance, medical allowance, house rent allowance and calculates the gross salary and display using cin cout stream objects:

25% dearness allowance.

15% medical allowance.

45% house rent allowance.

formula:

gross salary= basic pay + dearness allowance + medical allowance + house rent.

C++ Stream

The ‘cout’  C++ Stream Object:

The cout is pronounced as See Out. The cout stands for console output. The cout is a c++ standard output C++ stream object. It is used as an output statement to display.

Output on the computer screen. This C++ stream object represents the flow of data from computer memory to the display screen. It is a part of iostream.h header file.

C++ Stream

The  general syntax of cout is as follows:

cout<<const1/var1/exp1[<<consta2/var2/exp2/….];

where

cout:

it is the name of the output C++ stream object, which is used to display the standard output.

<<:

It is known as an insertion operator or put to the operator. It sends the output (contents of variable or constant) to the cout object. The cout object then sends the output to the display screen. We can use multiple insertion operators to display the value of multiple variables or constants.

Const1/var1/exp1, Const2/var2/exp2:

It indicates the list of constants, variables or arithmetic. Expression. for each constant, or variable, or expression. separated insertion operator (<<) is used. The string constant is given in double quotation marks. A character constant is given in single quotation marks. However, variables, numeric constants, and expression are given without quotation marks.

Examples:

  • The following statement will display a message “Electronic Clinic”:

Cout<<”Electronic Clinic”;

This output statement consists of only one string constant which is to be displayed on the screen. This string constant is given in double quotation marks.

  • The following statement will display the value of the variable ‘sum’ on the screen.

Cout<<sum;

Please note that in this output statement the variable ‘sum’ is not enclosed with any quotation marks.

  • The following statement uses one variable “km”, two string constants, one arithmetic expression, and four insertion operators:

Cout<<km<<” kilometers= “<< km*1000<<”meter”;

Suppose the value of km is 6. The output of the above output statement will be:

3 kilometers= 3000


Example: write a program that computes and displays the area of a square. The formula to compute the area of the square is using cout stream object:

Area = height * width;

Flowchart:

C++ Stream

Program:

C++ Stream

It the above program “Area of square =” is a text message. The text message will be displayed first and the value of the variable ‘area’ will be displayed.

Example: write a program that adds two floating-point values and displays the sum on the screen using cout stream object:

C++ Stream


Example: write a program that converts 45.6 centigrade temperature into Fahrenheit using the formula F=9/5(C+32) and displays the temperature in Fahrenheit using cout stream object:

C++ Stream

Example: write a program which converts age into moths and days using cout stream object:

C++ Stream

Example: write a program that displays values of integer, floating-point variable, and character variable on the screen using cout stream object:

C++ Stream


Example: write a program that calculates the distance covered by a body in 20.5 seconds. The initial velocity of the body is 15.8 meter per second and acceleration is 10.2m/sec2 using cout stream object:

Formula:

S=vit+1/2at2

Program:

C++ Stream

 

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About the Author: Engr Fahad

My name is Shahzada Fahad and I am an Electrical Engineer. I have been doing Job in UAE as a site engineer in an Electrical Construction Company. Currently, I am running my own YouTube channel "Electronic Clinic", and managing this Website. My Hobbies are * Watching Movies * Music * Martial Arts * Photography * Travelling * Make Sketches and so on...

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