C++ :: Determine Number Of Times Change Each Specific Character In String To Make It Palindrome

I'm trying to determine the number of times I have to change each specific character in a string to make it a palindrome. You can only change a character one at a time from the end.

Example: "abc" -> "abb" -> "aba" should print 2. "aba" will print 0 because it's already a palindrome. "abcd" -> "abcc" -> "abcb" -> "abca" -> "abba" will print 4 because it took 4 changes to make a palindrome.

I'm not too sure how to approach this - I figured out the case where if it's a palindrome (if reversed string is the same) then it'll print out a 0.

int main() {
int number;
cin >> number; //expecting a number for first line user input
for (int i = 0; i < number; i++) {
string str;

[Code] ....