C Syntax & Output | C Programming for Beginners - Class 6 PDF Download

Syntax

You have already seen the following code a couple of times in the first chapters. Let's break it down to understand it better:

Example

#include <stdio.h>

int main() {

  printf("Hello World!");

  return 0;

}

Example explained

• Line 1: #include <stdio.h> is a header file library that lets us work with input and output functions, such as printf() (used in line 4). Header files add functionality to C programs.

Don't worry if you don't understand how  #include <stdio.h> works. Just think of it as something that (almost) always appears in your program.

• Line 2: A blank line. C ignores white space. But we use it to make the code more readable.
• Line 3: Another thing that always appear in a C program, is main(). This is called a function. Any code inside its curly brackets {} will be executed.
• Line 4: printf() is a function used to output/print text to the screen. In our example it will output "Hello World".

Note that: Every C statement ends with a semicolon ;

Note: The body of int main() could also been written as:

int main(){printf("Hello World!");return 0;}

Remember: The compiler ignores white spaces. However, multiple lines makes the code more readable.

• Line 5: return 0 ends the main() function.
• Line 6: Do not forget to add the closing curly bracket } to actually end the main function.

C Output

Output (Print Text)

The printf() function is used to output values/print text:

Example

#include <stdio.h>

int main() {

  printf("Hello World!");

  return 0;

}

You can add as many printf() functions as you want. However, note that it does not insert a new line at the end of the output:

Example

#include <stdio.h>

int main() {

  printf("Hello World!");

  printf("I am learning C.");

  return 0;

}

C New Lines

To insert a new line, you can use the \n character:

Example

#include <stdio.h>

int main() {

  printf("Hello World!\n");

  printf("I am learning C.");

  return 0;

}

You can also output multiple lines with a single printf() function. However, be aware that this will make the code harder to read:

Example

#include <stdio.h>

int main() {

  printf("Hello World!\nI am learning C.\nAnd it is awesome!");

  return 0;

}

Tip: Two \n characters after each other will create a blank line:

Example

#include <stdio.h>

int main() {

  printf("Hello World!\n\n");

  printf("I am learning C.");

  return 0;

}