C program to print Hello World

This article will teach you how to print "Hello World" in C programming and provide you with the code to do so. The Hello World program is available in the following formats:

Print "Hello World" using a semicolon.
Print "Hello World" without using a semicolon.
Print "Hello World" 10 times using the for loop.
Print "Hello World" 10 times using the while loop.
Using string, print "Hello World".
Print "Hello World" using a user-defined function.

In C, print "Hello, World"

This program simply prints "Hello, World" using the printf() function. This function is defined in the stdio.h header file.

#include<stdio.h>
#include<conio.h>
int main()
{
    printf("Hello, World");
    getch();
    return 0;
}

This program was built and runs in the Code::Blocks IDE. Here is its sample output:

Print "Hello World" without using a semicolon

To print Hello World without using a semicolon (,), just put "Hello World" instead of "Hello, World" inside the printf() function as given in the previous program. Everything else is the same.

Using the for loop, print Hello World ten times

Now let's create another program that uses a for loop to execute the statement given below 10 times:

printf("Hello World\n");

as shown in the program given below:

#include<stdio.h>
#include<conio.h>
int main()
{
    int i;
    for(i=0; i<10; i++)
        printf("Hello World\n");
    getch();
    return 0;
}

Here is its sample run:

The loop works in such a way that:

Initially (at the very first run of the for loop), 0 gets initialized to i, and it is checked whether it is less than 10 or not.
The condition evaluates to true, therefore program flow goes inside the loop and executes the statement.
printf("Hello World");
that prints Hello World
Now the program flow goes to the loop update part. There, it increments the value of i and again checks the condition.
After every updated value of i, the program checks whether it is less than 10 or not.
Only program flow enters the loop if the condition is satisfied or evaluates to true. Otherwise, program flow exits from the loop.
As a result, "Hello World" appears 10 times on the output screen.

Using a while loop, print Hello World ten times

Now, instead of using the for loop, this program uses the while loop to do the same job as the previous program.

#include<stdio.h>
#include<conio.h>
int main()
{
    int i=0;
    while(i<10)
    {
        printf("Hello World\n");
        i++;
    }
    getch();
    return 0;
}

produces the same output as the previous program.

Using string, print "Hello World"

This program uses string to print "Hello World." That is, a variable, say str, of type char gets declared and initialized with "Hello World," and prints the value of str as output using the %s format specifier.

#include<stdio.h>
#include<conio.h>
int main()
{
    char str[20] = "Hello World";
    printf("%s", str);
    getch();
    return 0;
}

prints "Hello World" on the output.

Using Function, print Hello World

This is the last Hello World program that is created using a user-defined function, printHello(), that is being called from the main() function. That is, we have declared the function before main() and defined it after main(). Now we are free to call it from main(). When it gets called, then its definition part gets executed, which prints Hello World on the output.

#include<stdio.h>
#include<conio.h>
void printHello(void);
int main()
{
    printHello();
    getch();
    return 0;
}
void printHello(void)
{
    printf("Hello World");
}