Strcpy does not work correctly with char arrays

I get the following output when I run the code below:

Matrikel: 01717
Process finished with exit code -1073741571 (0xC00000FD)

Code:

char infos[255];
char matrikelnr[5];

sprintf(matrikelnr, "%d", s->matnr);
size_t n = strlen(matrikelnr);

while (n != 5) {
    memmove(matrikelnr + 1, matrikelnr, 5);
    matrikelnr[0] = '0';
    n = strlen(matrikelnr);
}

printf("Matrikel: %s", matrikelnr);
strcpy(&infos[0], matrikelnr);
printf("DEBUG");

I already tried: strcpy(infos[0], matrikelnr); and strcpy(infos[0], matrikelnr);

The strcpy seems to have a problem. Could you please help me with the solution?

Thanks already!

The main problem of your code is that you don't provide enough room for the string-terminating character '\0'. Each C string needs this to mark the end of the string. If you need to store strings with 5 characters, the variable needs to provide space for 6 characters.

However, your task can be solved much simpler, if you use standard formatting facilities. Change your call of sprintf() like this:

char matrikelnr[5 + 1];

sprintf(matrikelnr, "%05d", s->matnr);

The '0' is for using zeroes as filling character, and the '5' for a width of (at least) 5 characters.

I hope that your numbers are never greater than 99999.

Please read the documentation for details, and consider to use safer functions like snprintf().