Every C program contains a function called main. This is the start point of the program. Every function should return a value. In this program the function main returns no return value therefore we have written void main. We could also write this program as:
/* First Program to learn C */
#include <stdio.h>
main()
{
printf("This is a C program\n"); // printing a message
return 0;
}
Both the program are same and perform the same task. The result of both the program will print the following output on the screen:
This is a C program
#include<stdio.h> allows the program to interact with the screen, keyboard and file system of your computer. You will find it at the beginning of almost every C program.
main() declares the start of the function, while the two curly brackets show the start and finish of the function. Curly brackets in C are used to group statements together as in a function, or in the body of a loop. Such a grouping is known as a compound statement or a block.
printf("This is a C program\n"); prints the words on the screen. The text to be printed is enclosed in double quotes. The \n at the end of the text tells the program to print a new line as part of the output. printf() function is used for monitor display of the output.
Most of the C programs are in lower case letters. You will usually find upper case letters used in preprocessor definitions which will be discussed later, or inside quotes as parts of character strings.
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