Hello World Program in C

Here we will write two C programs to display Hello World on the screen. In the first program we are displaying the message using printf function and in the second program we are calling a user defined function and that function displays the Hello World message on the screen.

Example 1: Displaying Hello World

#include <stdio.h>
int main()
{
   /* printf function displays the content that is
    * passed between the double quotes.
    */
   printf("Hello World");
   return 0;
}

(code-box)

Output:

Hello World (code-box)

1. #include <stdio.h> – This statement tells compiler to include this stdio.h file in the program. This is a standard input output file that contains the definitions of common input output functions such as scanf() and printf(). In the above program we are using printf() function.

2. int main() – Here main() is the function name and int is the return type of this function. Every C program must have this function because the execution of program begins with the main() function. The 0 return value of this function represents successful execution of program while the return value 1 represents the unsuccessful execution of program. This is the reason we have return 0; statement at the end of this main function.

3. printf("Hello World"); – This function displays the content within double quotes as it is on the screen.

4. return 0; – As mentioned above, the value 0 means successful execution of main() function.

Example 2: Hello World Program using Functions

Lets see the same program using user defined function. In this program we have created a function hello() that prints the message on the screen. We are calling this function in the main() function. 

#include 
void hello(){
	printf("Hello World");
}
int main()
{
   //Calling a function here
   hello();
   return 0;
}