Essentials of C Program

Let's delve deeper into our introductory program:

Main


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#include <stdio.h> // preprocessor directive

int main() // the main function
{
	printf("Hello, c<>definity!\n"); // print text

	return 0; // exit
}

printf Function

The printf() function displays output on the screen. For our example, it shows the message "Hello, c<>definity!". Text meant for display should be wrapped in double quotes, like this:

Control Characters

Note

In C, \n is recognized as a single character, not two separate characters ("\" and "n").

The character sequence \n represents a newline. This means that any content following this sequence will appear on the next line.

Main


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#include <stdio.h> 

int main() 
{
	printf("Hel\nlo");

	return 0;
}

Throughout this course, we'll occasionally utilize the \t character for tabulation, which equates to a tab, or 4 spaces.

Main


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#include <stdio.h> 

int main() 
{
	printf("Hel\tlo");

	return 0;
}

The Semicolon

The semicolon ; signifies the end of a statement in C. Every statement in C should conclude with a ;. Think of it like the period at the end of a written sentence.

The Return Statement

return is the statement used to end a function and potentially return a value. In the context of the main function, the standard in C requires the use of return 0. While it has specific implications on UNIX systems, it generally indicates an "Exit status" or the successful termination of a program. We'll explore the return statement in greater depth as the course progresses.

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Section 1. Chapter 2