How to write a Hello World program in C language? To learn a programming language, you must start writing programs in it, and this could be your first C program. Let's have a look at the program first.
int main()
{
printf("Hello world\n");
return 0;
}
return_type function_name(arguments)
Return type specifies the type of value(s) if any returned by the function. A function must have a name to identify it. The function main is the starting point of the program which is called by the operating system.
Library function printf is used to display text on the screen, '\n' places the cursor at the beginning of the next line, "stdio.h" header file contains the declaration of the function.
The program's purpose is to get familiar with the syntax of the C programming language. In it, we have printed a particular set of words. To print whatever you want to, see C program to print a string.
Output:
Download Hello world C program.
C hello world using character variables
int main()
{
char a = 'H', b = 'e', c = 'l', d = 'o';
char e = 'w', f = 'r', g = 'd';
printf("%c%c%c%c%c %c%c%c%c%c", a, b, c, c, d, e, d, f, c, g);
return 0;
}
We have used seven-character variables, '%c' is used to display a character variable. See other efficient ways below.
We may store "hello world" in a string (a character array).
int main()
{
char s1[] = "HELLO WORLD";
char s2[] = {'H','e','l','l','o',' ','w','o','r','l','d','\0'};
printf("%s %s", s1, s2);
return 0;
}
Output:
HELLO WORLD Hello world
If you didn't understand this program, don't worry as you may not be familiar with the strings yet.
C Hello world a number of times
Using a loop we can display it a number of times.
int main()
{
int c, n;
puts("How many times?");
scanf("%d", &n);
for (c = 1; c <= n; c++)
puts("Hello world!");
return 0;
}
Hello world in C indefinitely
int main()
{
while (1) // This is always true, so the loop executes forever
puts("Hello World");
return 0;
}
To terminate the program press (Ctrl + C).