Pearls before Swine. For school, I am not a C++ developer and never will be.

NIM.cpp

#include <iostream>
#include <conio+.h>
#include <cmath>
#include <time.h>

using namespace std;

// SETTINGS
#define MIN_LINES 2
#define MAX_LINES 8
#define MIN_PEARL 1
#define MAX_PEARL 6
#define MISERE    TRUE
#define MOVE_WAIT TRUE

// MANIPULATORS:
double chartodouble(char* c) {
	double n = 0, in = 0;
	int t;
	bool dec = false, neg = false;
	for (int i=strlen(c)-1;i>=0;i--) {
		if ((t=c[i]-48)<10 && t>-1) {
			n += t*pow(10,in);
			in++;
			neg = false;
		} else if ((t==-2||t==-4) && !dec && in!=0) {
			n /= pow(10,in);
			in = 0;
			dec = true;
			neg = false;
		} else if (t==-3) neg = !neg;
	}
	if (neg) n *= -1;
	return n;
}
char* toLowerCase(char* c) {
	for (int i=0;i<(int)strlen(c);i++) c[i] = tolower(c[i]);
	return c;
}
int arrsum(int* a) {
	int s = 0;
	for (int i=1;i<(a[0]+1);i++) s += a[i];
	return s;
}

// GAME MECHANICS:
int *generate_level() {
	size_t s = rand() % (MAX_LINES+1-MIN_LINES) + MIN_LINES + 1;
	int *a = new int[s];
	a[0] = (int)s-1;
	for (size_t i=1;i<s;i++) a[i] = rand() % (MAX_PEARL+1-MIN_PEARL) + MIN_PEARL;
	return a;
	/* Returning an array from a function: http://www.cplusplus.com/forum/beginner/6644/ */
}
void draw_head() {
	clrscr();
	int l = (MAX_PEARL+5)/2-9;
	if (l<1) l = 1;
	for (int i=0;i<l;i++) cout << " ";
	cout << "PEARLS BEFORE SWINE" << endl;
	l = MAX_PEARL+5;
	if (l<21) l = 21;
	for (int i=0;i<l;i++) cout << "*";
	cout << endl << endl;
}
void draw_level(int* level, int hilight=0) {
	draw_head();
	for (int i=1;i<(level[0]+1);i++) {
		if (i==hilight) cout << ">" << i << ": ";
		else cout << " " << i << ": ";
		for (int j=0;j<level[i];j++) {
			cout << "O";
		}
		cout << endl;
	}
	cout << endl;
}
int *AI(int* a) {
	int X = 0, chosen_heap, nb_remove, heaps_twomore = 0, heaps_one = 0;
	for (int i=1;i<(a[0]+1);i++) X = X^a[i];
	if (X==0) {
		/* New: remove random number of pearls from random row. */
		int row, before;
		do {
			row = rand()%(a[0]+1)+1;
			before = a[row];
			if (a[row]>0) {
				if (a[row]==1) a[row] = 0;
				else a[row] = rand()%a[row];
			}
		} while (before<1);
		/* Original: remove the first row with more than 0 pearls completely.
		for (int i=1;i<(a[0]+1);i++) {
			if (a[i]>0) {
				//a[i] = 0;
				a[i] = a[i]-1;
				break;
			}
		}*/
	} else {
		for (int i=1;i<(a[0]+1);i++) {
			if ((a[i]^X)<a[i]) chosen_heap = i;
		}
		nb_remove = a[chosen_heap] - (a[chosen_heap]^X);
		for (int i=1,n;i<(a[0]+1);i++) {
			if (chosen_heap==i) n = a[i]-nb_remove;
			else n = a[i];
			if (n>1) heaps_twomore += 1;
		}
		if (heaps_twomore==0) {
			for (int i=1;i<(a[0]+1);i++) {
				if (a[i]>a[chosen_heap]) chosen_heap = i;
			}
			for (int i=1;i<(a[0]+1);i++) {
				if (a[i]==1) heaps_one++;
			}
			if (heaps_one%2!=(int)MISERE) nb_remove = a[chosen_heap]-1;
			else nb_remove = a[chosen_heap];
		}
		a[chosen_heap] = a[chosen_heap] - nb_remove;
	}
	return a;
	/* Ported from Wikipedia's Python implementation: http://en.wikipedia.org/wiki/Nim#Mathematical_theory */
}

// PLAY THE GAME:
int main() {
	if (
		MIN_LINES<2||
		MIN_PEARL<1||
		MAX_LINES<MIN_LINES||
		MAX_PEARL<MIN_PEARL||
		!(MISERE==0||MISERE==1)||
		!(MOVE_WAIT==0||MOVE_WAIT==1)
	) {
		cout << "The game can not run with the current settings...";
		_getch();
		return 0;
	}
	srand((int)time(0));
	bool play = true;
	do {
		int* level = generate_level();
		char input[50];
		int row, qty, last;
		do {
			draw_level(level);
			cout << "Do you want to start? (Y/N)" << endl << "> ";
			cin >> input;
			toLowerCase(input);
		} while (
			strcmp("n",input)!=0&&
			strcmp("no",input)!=0&&
			strcmp("y",input)!=0&&
			strcmp("yes",input)!=0
		);
		if (input[0]=='n') level = AI(level);
		if (arrsum(level)==(int)MISERE) {
			draw_level(level);
			cout << "You lost.";
		} else {
			do {
				row = 0, qty = 0;
				do {
					draw_level(level);
					cout << "Pick a row." << endl << "> ";
					cin >> input;
					row = (int)chartodouble(input);
					if (row>level[0]||row<1||level[row]==0) row = 0;
				} while (row==0);
				do {
					draw_level(level,row);
					cout << "Number of pearls to remove." << endl << "> ";
					cin >> input;
					qty = (int)chartodouble(input);
					if (qty>level[row]||qty<1) qty = 0;
				} while (qty==0);
				level[row] = level[row]-qty;
				last = 0;
				if (arrsum(level)>1) {
					if (MOVE_WAIT) {
						draw_level(level);
						cout << "Computer wants to move." << endl << "Press any button...";
						_getch();
					}
					AI(level);
					last = 1;
				}
			} while (arrsum(level)>1);
			draw_level(level);
			cout << "WINNER: ";
			if (last==(int)MISERE) cout << "COMPUTER!";
			else cout << "YOU!";
			_getch();
			do {
				draw_head();
				cout << "Play again? (Y/N)" << endl << "> ";
				cin >> input;
				toLowerCase(input);
			} while (
				strcmp("n",input)!=0&&
				strcmp("no",input)!=0&&
				strcmp("y",input)!=0&&
				strcmp("yes",input)!=0
			);
			if (input[0]=='n') play = false;
		}
	} while(play);
	return 0;
}