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cout<< "Hello World";
getch();
}
DOSBox 0.74, Cpu speed: max 100%
Now if you run the program, the output screen will appear. To Hello World_
get back to the editor, press the Enter key.
Output
STRUCTURE OF A C++ PROGRAM
A program is a set of statements, where each statement has a specific meaning and purpose. To
understand the program better, let’s number each line of the code:
#include<iostream.h> // Line 1
#include<conio.h> // Line 2
void main() // Line 3
{ // Line 4
clrscr(); // Line 5
cout<<"Hello World"; // Line 6
getch(); // Line 7
} // Line 8
Line 1: The # symbol indicates a preprocessor directive. It instructs the compiler to include
the iostream.h header file before compilation. This header file provides predefined objects
such as cout, which is used for displaying output. Without including iostream.h, the cout
object cannot be used.
Line 2: This line includes the conio.h header file. The conio.h file provides predefined
functions such as getch(), which is used for handling console input.
Line 3: This line defines the main() function, which serves as the entry point of the program.
Every C++ program must have a main() function, as execution starts from this function.
Line 4: The opening curly brace { marks the beginning of the main() function’s body.
Line 5:The clrscr(); function is used to clear the console screen before displaying output. This
ensures that any previous output does not interfere with the current program output.
Line 6: This line contains the cout object, which is used to print messages on the output
screen. The message to be displayed must be enclosed in double quotes. In this case, it prints
"Hello World". At the end of the line, a semicolon (;) is used as a statement terminator. In
C++, each statement must end with a semicolon.
Line 7: The getch() function is used to pause the program execution until a key is pressed.
This ensures that the output window remains open until the user interacts with the keyboard.
Line 8: The closing curly brace } marks the end of the main() function.
11
Introduction to C++

