Question

i want to add “/.” to a file name, for example,
i have file name “abc”, i want to get a name “abc/.abc”,
how to do it in C?
strcpy(“/.”,name) and strcat(“/.”,name) returned segmentation fault.

Thanks

Answer 1

The first parameter to strcat must be a modifiable string with enough space allocated to hold the resulting string and the terminating zero byte. The first parameter to strcpy must point to allocated, modifiable memory with sufficient space to hold the resulting copy of the string and the terminating zero byte. In both of your examples, you have passed a constant as the first parameter.

Here’s some example code to do what you want:

char* SlashDotter(const char* in)
{ // turn <string> into <string>/.<string> -- caller must free returned string
 char *out = malloc(strlen(in)*2 + 3); // two copies of input, /, ., and nul
 strcpy(out, in);
 strcat(out, "/.");
 strcat(out, in);
 return out;
}