strcat problems
Author
Could someone tell me whats wrong ?
int num_pages = get_total_text_pages();
char buffer[5];
for(int i=0; i<MAX_PAGES; i++) { // Marked Pages
if(i<=num_pages) {
string_before = "<page nr='";
_itoa(i+1, buffer, 10);
strcat(string_before, buffer);
strcat(string_before, "' marked='");
if(StrToInt(find_in_text(S, string_before, '\'')) == 1)
set_marked_pages(i, true);
else
set_marked_pages(i, false);
}else
set_marked_pages(i+1, false);
}
Thanks in advance
The problem is
string_before = "<page nr='";
To expand on that slightly, string_before is a pointer to a character. The expression string_before = "<page nr="; makes string_before point to the first character of the constant string "<page nr=", which will probably be stored in the programs data segment. The function strcat appends it's second argument to the end of it's first argument. It requires that it's first argument has sufficient allocated memory to contain both strings. In your case you don't. You're not even allowed to write into the data segment. Instead you should do something like one of the following:
Pure C:
C++:
Enigma
Pure C:
int num_pages = get_total_text_pages();int required_size;char * string_before;for (int i = 0; i < MAX_PAGES; ++i){ if (i < num_pages) { required_size = snprintf(0, 0, "<page nr='%i' marked='", i + 1); if (required_size > 0) { string_before = (char *)malloc(required_size + 1); if (!string_before || snprintf(string_before, required_size + 1, "<page nr=%i marked='", i + 1) != required_size) { // error } } else { // error } // the rest of your code free(string_before); }}C++:
int num_pages = get_total_text_pages();for (int i = 0; i < MAX_PAGES; ++i){ std::string string_before = "<page nr='" + boost::lexical_cast< std::string >(i + 1) + "' marked='"; // rest of your code, possibly using string_before.c_str() if interfacing with C code.}Enigma
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