❮ C Exercise Example24 C Examples Joseph Life Dead Game ❯

C Program Structure

Before we learn the basic building blocks of C language, let's take a look at the structure of a minimal C program, which we can refer to in the following sections.

C Hello World Example

A C program mainly includes the following parts:

Preprocessor directives
Functions
Variables
Statements & expressions
Comments

Let's look at a simple code snippet that outputs the word "Hello World":

Example

#include <stdio.h>

int main()
{
   /* My first C program */
   printf("Hello, World! \n");

   return 0;
}

Next, we will explain the above program:

The first line, #include <stdio.h>, is a preprocessor directive that tells the C compiler to include the stdio.h file before actual compilation.
The next line, int main(), is the main function where the program execution begins.
The line with /.../ will be ignored by the compiler and is used to place comments in the program. They are known as program comments.
The next line, printf(...), is another function available in C that displays the message "Hello, World!" on the screen.
The line, return 0;, terminates the main() function and returns the value 0.

Compiling & Executing a C Program

Let's see how to save the source code in a file and how to compile and run it. Here are the simple steps:

Open a text editor and add the above code.
Save the file as hello.c.
Open the command prompt and navigate to the directory where the file is saved.
Type gcc hello.c and press Enter to compile the code.
If there are no errors in the code, the command prompt will move to the next line and generate an a.out executable file.
Now, type a.out to execute the program.
You will see "Hello World" displayed on the screen.
```
$ gcc hello.c
$ ./a.out
Hello, World!
```

Make sure your path includes the gcc compiler and that you run it in the directory containing the source file hello.c.

If you have multiple C source code files, compile them as follows:

$ gcc test1.c test2.c -o main.out
$ ./main.out

test1.c and test2.c are the two source code files.

❮ C Exercise Example24 C Examples Joseph Life Dead Game ❯