First C Program
What is a computer program?A computer program is set of instructions telling the computer to accomplish a desired task. A task is calculating an equation. A task is printing an output to the screen when asked upon. A task is taking an input and saving it in the memory.
How do we write a computer program for a given task?
You write a computer program using a computer programming language, C is such a language. The language has syntax or set of rules as to how to tell the computer to accomplish a given task.
Can we write a computer program?
Yes. We'll start with the traditional introductory program.
Consider the program below.
/*Project: First Program */
/*File: Hello.c */
/*Aim: Traditional Intro */
#include <stdio.h>
main()
{
printf("Hello, world\n");
}
What does this program exactly do?
First of all, you will need some time to become familiar with many of the conventions of writing a program. As you start writing programs yourself, you will become familiar with the conventions.
This program prints: Hello, world to the screen or to the console.
I suppose printf("Hello, world\n"); is the instruction telling the computer to print Hello, world to the screen or console. What are the other instructions used for?
/*Project: First Program */ /*File: Hello.c */ /*Aim: Traditional Intro */
The above are comments. Whatever typed inside /* */ are comments. Comments are not instructions, and not part of the program to accomplish tasks. The comments areuseful for the programmer as documentation.
include <stdio.h>
An instruction telling the computer to use the library file stdio.h. We'll discuss more about this later; now just include this in all programs.
main()
An instruction telling the computer to create a main module.
{
A syntax requirement. The compiler needs that in order to properly compile the program.
printf("Hello, world\n");
The instruction telling the computer to print Hello, world.
}
A syntax requirement. The compiler needs that in order to properly compile the program.