Input and output in C Plus Plus

A very detailed tutorial for beginners about how to input and output data in C++
Using the standard input and output library, we will be able to interact with the user by printing messages on the screen and getting the user's input from the keyboard.

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Basic Input/Output
Using the standard input and output library, we will be able to interact with the user by printing messages on the screen and getting the user's input from the keyboard.


Basic Input/Output
Until now, the example programs of previous sections provided very little interaction with the user, if any at all. Using the standard input and output library, we will be able to interact with the user by printing messages on the screen and getting the user's input from the keyboard.
C++ uses a convenient abstraction called streams to perform input and output operations in sequential media such as the screen or the keyboard. A stream is an object where a program can either insert or extract characters to/from it. We do not really need to care about many specifications about the physical media associated with the stream - we only need to know it will accept or provide characters sequentially.
The standard C++ library includes the header file iostream, where the standard input and output stream objects are declared.


Input/Output with files
C++ provides the following classes to perform output and input of characters to/from files:


Input / Output Tutorial
Designed for beginners in C++, this tutorial presents several examples showing you how to cout/cin, work with arrays, and display data.


Creating a simple calculator
In this tutorial we will create a very simple calculator in C++ using only the basics of C++ like variables, input/output and if/else/else if statements


File I/O in C++ : part 1 of 2
This tutorial will start with the very basis of File I/O (Input/Output) in C++. After that, I will look into aspects that are more advanced, showing you some tricks, and describing useful functions.
You need to have good understanding of C++, otherwise this tutorial will be unfamiliar and not useful to you!


Learn how to Program in C++
The basics of C++ console programming. Free tutorials for beginners. Easy to follow console applications. A C++ Console application (text input / text output to the console window), is the easy way to learn all the fundamentals of C++ programming.


Data Input/Output
The values and expressions used in C++ are displayed using the cout extractor. To make the displaying of data more realistic, the cout is configured to handle or format data to any desired result. While the cout (as a class) is defined in the iostream file, some other files provide other extensive techniques for displaying data to the console. The C language also is equipped with other formatting functions used for the same purpose. The ability to create a program made of mixed C and C++ language enhances these formatting possibilities.


Reading data from user (user input)
This C++ code showing how to read data (an integer) from user (user input).


Using the printf() function
A guide to the famous printf() function in C. Shows you how to output data in several ways. The tutorial is not yet complete but will be continued soon.


Loops
Loops are used to repeat a block of code. Being able to have your program repeatedly execute a block of code is one of the most basic but useful tasks in programming -- many programs or websites that produce extremely complex output (such as a message board) are really only executing a single task many times.


Bison Tracking
Why the Fortran would anyone want to do this? (Pardon my language). It's because C++ parsers that you make yourself:
-Produce more human friendly code For starters, the files that Flex and Bison output can be very hard to understand, even if they do have some decent comments. This can make them hard to integrate into other programs. However, since you wrote most of this and hopefully read this article, you have an idea of what's going on.
They also have a tendency of being large.


Variables. Data Types.
The usefulness of the "Hello World" programs shown in the previous section is quite questionable. We had to write several lines of code, compile them, and then execute the resulting program just to obtain a simple sentence written on the screen as result. It certainly would have been much faster to type the output sentence by ourselves. However, programming is not limited only to printing simple texts on the screen. In order to go a little further on and to become able to write programs that perform useful tasks that really save us work we need to introduce the concept of variable.


Dynamic Memory
Until now, in all our programs, we have only had as much memory available as we declared for our variables, having the size of all of them to be determined in the source code, before the execution of the program. But, what if we need a variable amount of memory that can only be determined during runtime? For example, in the case that we need some user input to determine the necessary amount of memory space.


Dynamic Memory
Until now, in all our programs, we have only had as much memory available as we declared for our variables, having the size of all of them to be determined in the source code, before the execution of the program. But, what if we need a variable amount of memory that can only be determined during runtime? For example, in the case that we need some user input to determine the necessary amount of memory space.


If Statements
The ability to control the flow of your program, letting it make decisions on what code to execute, is valuable to the programmer. The if statement allows you to control if a program enters a section of code or not based on whether a given condition is true or false. One of the important functions of the if statement is that it allows the program to select an action based upon the user's input.