C is a general-purpose programming language created by Dennis Ritchie at the Bell Laboratories in 1972
.
It is a very popular language, despite being old.
C is strongly associated with UNIX, as it was developed to write the UNIX operating system.
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It is one of the most popular programming language in the world
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If you know C, you will have no problem learning other popular programming languages such as Java, Python, C++, C#, etc, as the syntax is similar
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C is very fast, compared to other programming languages, like Java and Python
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C is very versatile; it can be used in both applications and technologies
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C++ was developed as an extension of C, and both languages have almost the same syntax
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The main difference between C and C++ is that C++ support classes and objects, while C does not
To start using C, you need two things:
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A text editor, like Notepad, to write C code and in this tutorial we will be using Visual Studio Code
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A compiler, like GCC, to translate the C code into a language that the computer will understand
Let's create our first C file.
#include <stdio.h>
int main() {
printf("Hello World!");
return 0;
}
After build and run...
Hello World!
Process returned 0 (0x0) execution time : 0.011 s
Press any key to continue.
You have already seen the following code a couple of times in the first chapters. Let's break it down to understand it better:
#include <stdio.h>
int main() {
printf("Hello World!");
return 0;
}
Example explained
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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.
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Line 2: A blank line. C ignores white space. But we use it to make the code more readable.
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Line 3: Another thing that always appear in a C program, is
main()
. This is called a function. Any code inside itscurly 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
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Line 5:
return 0
ends themain()
function. -
Line 6: Do not forget to add the
closing curly bracket }
to actually end the main function.
To output values or print text in C, you can use the printf()
function:
#include <stdio.h>
int main() {
printf("Hello World!");
return 0;
}
You can use as many printf()
functions as you want. However, note that it does not insert a new line at the end of the output:
#include <stdio.h>
int main() {
printf("Hello World!");
printf("I am learning C.");
return 0;
}
Let's see the output...
Hello World!I am learning C.
Process returned 0 (0x0) execution time : 0.011 s
Press any key to continue.
To insert a new line, you can use the \n
character:
#include <stdio.h>
int main() {
printf("Hello World!\n");
printf("I am learning C.");
return 0;
}
Output:
Hello World!
I am learning C.
Process returned 0 (0x0) execution time : 0.011 s
Press any key to continue.
Tip: Two \n
characters after each other will create a blank line:
#include <stdio.h>
int main() {
printf("Hello World!\n\n");
printf("I am learning C.");
return 0;
}
Output:
Hello World!
I am learning C.
Process returned 0 (0x0) execution time : 0.011 s
Press any key to continue.
The newline character (\n
) is called an escape sequence, and it forces the cursor to change its position to the beginning of the next line on the screen. This results in a new line.
Other valid escape sequences are:
Escape Sequence | Description |
---|---|
\t | Creates a horizontal tab |
\\ | Inserts a backslash character (\) |
" | Inserts a double quote character |
- Mengsreang-Chhoeung @mengsreang_dev