simple char array access causes crash- why??

This very simple function is crashing and I cant see why- every time I try to change the value of str[i] I get an access violation, and I don't understand why this is happening- anybody know?How did you call this function? What parameter did you pass?

This will *not* work:

#include <cstring>

void ChangeToSpace (char* str)
{
size_t n = strlen(str) ;
for (size_t i = 0; i < n; i++)
{
str[i] = 0x20;
}
}

int main()
{
ChangeToSpace("abc123"); // string literal -- cannot be changed
}

String literals cannot be changed. If you do that, the behaviour is undefined. The program will more than likely crash.

Regards,

Paul McKenzie

Your program (same as Pauls sample), has a pointer to a fixed literal. Either copy the literal into a buffer, or even better stop using 30 year old techniques, and use proper STL strings.

Are you not allowed to change the entries in a char array?Yes, you can change the entries in a char array. The problem is that what you declared is not an array -- it is a string literal.

char *p = "abc123"; // string literal, cannot be changed
char p2[] = "abc123"; // an array of char, which can be changed.

Regards,

Paul McKenzie