setting a file path?

Hi,

I am new in programming C++ with RAD Studio on Win10. I have a very simple Problem but cannot solve it:

In a program I want to define a file Name and then open the file

char fname[] = "Z:\Daten\letzte400Pulse_1.txt";
fin=fopen(fname,"rt");

But  fin is NULL, and the Debugger Shows for fname "Z:Datenletzte400Pulse_1.txt\0". The backslashes are ignored.

How shall I define a file path for Win10 containing "\" ?