c++ for loop is being skipped - c++

Question

What am I doing wrong with this small program.
I'm just starting to learn c++, and by all mean I can accept this as a moot question. I'm reading through the Prata c++ primer and it gave me a code example which takes a char array and uses strcmp() in a for loop which iterates sequentially through the ASCII code starting with '?' until a test char variable ==s a set value from another char.
Thinking I could outdo the book I tried to create a similar program which takes a char array and using a for loop will take a test char array and iterate through each value of the array until the two variables are equal.
I simplified the program to only take the first of each array in the for loop because I was experiencing a problem where the program seems to simply skip over the for loop and terminate.
Below are first the prata code snippet, followed by my piece of code. Any feedback (even abusive >_<) would be useful.
#include <iostream>
#include <cstring>
int main() {
using namespace std;
char word[5] = "?ate";
for (char ch = ‘a’; strcmp(word, "mate"); ch++) {
cout << word << endl;
word[0] = ch;
}
cout << "After loop ends, word is " << word << endl;
return 0;
}
My code (though maybe poorly done, I can accept that)
#include <iostream>
#include <cstring>
int main() {
using namespace std;
char word[5] = "word";
char test[5] = "????";
int j = 0;
int i = 0;
cout << "word is " << word << "\nTest is " << test << endl;
cout << word[0] << " " << test[0] << endl;
for (char temp = '?'; word[0] == test[0] || temp == 'z'; temp++) {
if ((word[i]) == (test[j])) {
test[j] = temp;
j++;
temp = '?';
}
test[j] = temp++;
cout << test << endl; //Added to see if the for loop runs through once,
//which is does not
}
return 0;
}

Answer 1

Your for loop never starts because your condition, shown here:
word[0] == test[0] || temp == 'z'
will always return false on its first pass. Since temp is initialized to '?' and word[0] (w) does not equal test[0] (?), your loop will never start.
Also, you've initialized temp to ? so, looking at an ascii chart, you'll see that there's a lot of non-alpha characters between ? and a lower case z.
Furthermore, within the for loop, you increment j (j++) but never touch i. Since you're reading chars from word with i as your index, test would end up being "wwww".
You seem to be confusing yourself so...
Lets break down what you're trying to do:
If you're iterating every character in a string, then checking each letter of the alphabet at that index, you're going to have two loops:
for(;;) {
for(;;) {
}
}
The first (iterating through each index in the string should end when the index reaches the end of the string (strings literals are terminated with a '\0'):
for(int i = 0; word[i] != '\0' && test[i] != '\0'; i++) {
for(;;) {
}
}
The second will check each letter of the alphabet (char temp = 'a' and temp++) against your given index in both word and test (word[i] != test[i];). If they're not equivalent, it will set the character of test at index i to temp until it finds the right letter. Putting it all together, you end up with this:
for(int i = 0; word[i] != '\0' && test[i] != '\0'; i++) {
for(char temp = 'a'; word[i] != test[i]; temp++) {
test[i] = temp;
}
}
Of course, if you were only going for results and not trying to teach yourself about loops and programming basics, this is all just a very roundabout way of simplay calling:
memcpy(temp, word, strlen(word));