C

C is another moderne high-level computer programming language. It is widespread, so e.g. the Unix operating system was written in C.

Above all, C impresses with an ingenious and extremely compact, versatile and original syntax!

The widespread server programming language PHP largely adopts as well the syntax of C; and PHP itself was written in C!

The Book I read: Programmieren in C, written by
Kernighan/ Ritchie, ISBN 3-446-13878-1.

It is a very good and detailed book that I actually can recommend to you!