The C main program

As a first example people usually write the

“Hello World” program

#include <stdio.h>

void main() {

printf(“Hello World!\n”);

}

Let us try to compile and execute this program

First we start the editor, we type and save the program,

then we compile it using the gcc compiler and finally we execute it.

C data types

• C has a number of data types:
• char, short, int, long, float, double
• unsigned char, unsigned short, unsigned int
• can be extended to boolean (in C99 you can #include <stdbool.h>
• No strings! But a pointer to a zero terminated chain of characters
• struct
• union
• enum

Assignements

We modify the program to do some calculation:

Slide 1: A bit of C programming

Lecture 3

Uli Raich

Slide 2: Programming Languages

To make a language a programming language it needs to implement:

• Assignments
• Conditional statements
• loops

Slide 3: C libraries

C uses a large number of code libraries and you can create C libraries yourself.

These libraries may use special data types, which are defined in include files

Before using the library functions

#include <stdio.h>

or

#include “myOwnIncludeFile.h”

-- Uli Raich - 2017-09-07

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