C++ :: Append Suffix To String With Pointer Arithmetic

Dynamic memory allocation and pointer arithmetic with char arrays.

The class was given to me in a very basic skeleton form with prototypes but no implementations, along with a test function to test my implementations. I CAN NOT use any C String functions in this assignment.

The part of the program which is troubling is the append function, which just appends a parameter string215 object to the end of the current string215 object.

// Add a suffix to the end of this string. Allocates and frees memory.
void string215::append(const string215 &suffix) {
char *output = new char[str_len(data)+suffix.length()+1];
for(int x = 0; x < str_len(data); x++) {
*output = *data;

[Code]...

This portion of the code is tested in the 13th test of the test function as shown here:

string215 str("testing");
...

// Test 13: test that append works in a simple case.
curr_test++;
string215 suffix("123");
str.append(suffix);
if (strcmp(str.c_str(), "testing123") != 0) {
cerr << "Test " << curr_test << " failed." << endl;
failed++;
}

Here is the description of the append class: Add the suffix to the end of this string. Allocates a new, larger, array; copies the old contents, followed by the suffix, to the new array; then frees the old array and updates the pointer to the new one.

My program aborts at the very end of the append function execution with the error message:

Debug Assertion Failed!

Program: [Source path]dbgdel.cpp
Line: 52

Expression: _BLOCK_TYPE_IS_VALID(pHead->nBlockUse)
...

Abort || Retry || Ignore

Here's a pastebin of the .cpp and .h file for this program

string215.cpp: [URL] ....
string215.h: [URL] .....