Question

Ok, I’m really confused by this behaviour in VS2008.

This code..

char data[512] = "";

char c[1] = "";
c[0] = '1';

strcat(data, c);

.. results in data being set to this string value: 1ÌÌÌÌhÿ

Surely it should just be 1?

How can I ensure data only contains the single char[] that I copy into it (i.e. 1)?

Why does strcat() copy all that garbage? Why does c even contain that garbage?

Thanks for any help

Edit: Thanks all.

Answer 1

The problem here is that you are passing an invalid value to strcat. It expects the second parameter to be a valid c string value. To be valid it must be an array / pointer of char values which ends with a null terminator (\0). The value your are passing does not contain a null terminator and is hence invalid.

You need to define a null terminator for the string value c to be valid. For example

char c[2];
c[0] = '1';
c[1] = '\0';