Learn Programming with C++

Learn Programming with C++

C++in the mid 1980s. C++is an extension of the programming language C, a product of AT&T Bell Labs from the early 1970s. C++’s close relationship to C allows C++ programs to utilize a large collection of code developed in C.

Source code to target code sequence Structure

Examples of software written in C++ include Microsoft Windows 8, Microsoft Office, macOS, and Adobe Creative Suite.

the needs of commercial software development and accomplish all that it does, C++ itself is complex.

Writing a C++ Program

Properly written C++ programs have a particular structure. The syntax must be correct, or the compiler will generate error messages and not produce executable machine language. This chapter introduces C++ by providing some simple example programs and associated fundamental concepts. Most of the concepts presented in this chapter are valid in many other programming languages as well.

General Structure of a Simple C++ Program

#include <iostream>
int main() 
{
     std::cout << "This is a simple C++ program!\n";
}

Output

This is a simple C++ program!

#include This line is a preprocessing directive. All preprocessing directives with in C++ sourcecodebeginwith a # symbol.

int main() { This specifies the real beginning of our program. Here we are declaring afunction named main. All C++ programs must contain this function to be executable.

std::cout << "This is a simple C++ program!\n"; 

The body of our main function contains only one statement. This statement directs the executing program to print the message This is a simple C++ program! on the screen. A statement is the fundamental unit of execution in a C++ program. Functions contain statements that the compiler translates into executable machine language instructions.

Variations of our simple program

#include <iostream>
using std::cout;
int main() 
{ 
    cout << "This is a simple C++ program!\n"; 
}

#include <iostream>
using namespace std;
int main() 
{
     cout << "This is a simple C++ program!\n"; 
}

The statement in the main function in any of the three versions of our program uses the services of an object called std::cout. The std::cout object prints text on the computer’s screen. The text of the message asitappearsin the C++ source code is called a string, for string of characters.

Arrow C program

#include <iostream>
int main() 
{ 
    std::cout << " * \n"; 
    std::cout << " *** \n"; 
    std::cout << " ***** \n"; 
    std::cout << " * \n"; 
    std::cout << " * \n"; 
    std::cout << " * \n"; 
}

constitute the body of the main function. The body consists of all the statements between the open curly brace({)and close curly brace(}). We say that the curly braces delimit the body of the function. The word delimit means to determine the boundaries or limits of something

Template for simple C++ programs

Our programs generally will print something, so we need the #include directive that brings the std::cout definition from into our program. Depending on what we need our program to do, we may need additional #include directives. The main function definition is required for an executable program, and we will fill its body with statements that make our program do as we wish.

Exercises

• 1.What preprocessor directive is necessary to use statements with the std::cout printing stream object?
• 2. What statement allows the short namecoutto be used instead ofstd::cout?
• 3. What does the namestdstand for?
• 4. All C++ programs must have a function named what?
• 5. The body ofmainis enclosed within what symbols?
• 6. What operator directs information to thestd::coutoutput stream?
• 7. Write a C++ program that prints your name in the console window.