Small tricky Point For New Learner, NEED HELP!

[submeyar]

INTRODUCTION OF CODE:
This is a small game, named Subtracting Game. here User and Computer Subtract the Specific Number that they decided to be subtracted from the Total and make it Zero. BTW nice game for Newbies.

Well short Intro.Please compile the CODE to understand what the Program do.

NEED LITTLE HELP:
Here is a Small Problem i dont Understand the only one Point of this CODE. and that is “remainder = total % (delta + 1);”, OK i know About Modulus and knows what it does. The only thing that i dont know is That why the Programmer has added “1” to delta, actually what is his intention.

As a programmer do you think that this is a bit tricky point of this program ? “remainder = total % (delta + 1);”.

CODE :

#include <iostream>

using namespace std;

int main() {
int total, n;
int delta = 0;  // Max. number to subtract by each turn.
int remainder = 0;

cout << “Welcome to NIM. Pick a starting total: “;
cin >> total;
while (total < 1) {
cout << “Enter positive integer only. ” << endl;
cout << “Pick starting total: “;
cin >> total;
}
cout << “What should be the max. number to subtract? “;
cin >> delta;
while (delta < 1 || delta >= total) {
cout << “Enter positive integer only. ” << endl;
cout << “Num must be less than starting total. ” << endl;
cout << “Pick max. number to subtract: “;
cin >> delta;
}
while (true) {

// Pick best response and print results.
// Divide total by delta and use remainder
//  as the number to subtract by.

remainder = total % (delta + 1);

if (remainder > 0) {
total = total – remainder;
cout << “I am subtracting ” << remainder << “.” << endl;
} else {
total–;
cout << “I am subtracting 1.” << endl;
}
cout << “New total is ” << total << endl;
if (total == 0) {
cout << “I win!” << endl;
break;
}

// Get user’s response; must be in range 1 to delta.

cout << “Enter number to subtract, “;
cout << “from 1 to ” << delta << “: “;
cin >> n;
while (n < 1 || n > delta) {
cout << “Input must be 1 to ” << delta << “. ” << endl;
cout << “Re-enter: “;
cin >> n;
}
total = total – n;
cout << “New total is ” << total << endl;
if (total == 0) {
cout << “You win!” << endl;
break;
}
}
system(“PAUSE”);
return 0;
}

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