C Comments

Comments in C

Comments can be used to explain code, and to make it more readable. It can also be used to prevent execution when testing alternative code.

Comments can be singled-lined or multi-lined.

Single-line comments start with two forward slashes (//).

Any text between // and the end of the line is ignored by the compiler (will not be executed).

This example uses a single-line comment before a line of code:

// This is a comment
printf("Hello World!");

This example uses a single-line comment at the end of a line of code:

printf("Hello World!"); // This is a comment

Multi-line comments start with /* and ends with */.

Any text between /* and */ will be ignored by the compiler:

/* The code below will print the words Hello World!
to the screen, and it is amazing */
printf("Hello World!");

It is up to you which you want to use. Normally, we use // for short comments, and /* */ for longer.

Good to know: Before version C99 (released in 1999), you could only use multi-line comments in C.