Help with math game program.

[Matt Hintzke]

I am developing a program for a class in which different levels have different types of basic arithmetic using the 4 operands, +, -, *, and /.

here is my code for the game:

int start_game(int difficulty, int score){
	int integer1=0, integer2=0, integer3=0, integer4=0, operand1 = -1, operand2 = -1, operand3 = -1, check, counter = -1;
	double real_ans, user_ans;
	char char_op1, char_op2, char_op3;
	do
	{
	system("cls");
	switch(difficulty)
	{
	case 1:
			integer1 = (rand()%9)+1;
			integer2 = (rand()%9)+1;
			integer3 = (rand()%9)+1;
			operand1 = (rand()%2);
			operand2 = (rand()%2);
			if(operand1 == 0)
			{
				char_op1 = '+';
			}else{
				char_op1 = '-';
			}
			if(operand2 == 0)
			{
				char_op2 = '+';
			}else{
				char_op2 = '-';
			}
			printf("Equation %d: %d %c %d %c %d\n\n", (counter+2), integer1, char_op1, integer2, char_op2, integer3);
			break;
	case 2:
			integer1 = (rand()%9)+1;
			integer2 = (rand()%9)+1;
			operand1 = (rand()%2)+2;
			if(operand1 == 2)//*
			{
				char_op1 = 'x';
			}else{
				char_op1 = '/';
			}
			printf("Equation %d: %d %c %d\n\n", (counter+2), integer1, char_op1, integer2);
			break;
	case 3:
			integer1 = (rand()%9)+1;
			integer2 = (rand()%9)+1;
			integer3 = (rand()%9)+1;
			operand1 = (rand()%4);
			operand2 = (rand()%4);
			switch(operand1)
			{
			case 0:
				char_op1 = '+';
				break;
			case 1:
				char_op1 = '-';
				break;
			case 2:
				char_op1 = 'x';
				break;
			case 3:
				char_op1 = '/';
				break;
			}
			switch(operand2)
			{
			case 0:
				char_op2 = '+';
				break;
			case 1:
				char_op2 = '-';
				break;
			case 2:
				char_op2 = 'x';
				break;
			case 3:
				char_op2 = '/';
				break;
			}
			printf("Equation %d: %d %c %d %c %d\n\n", counter, integer1, char_op1, integer2, char_op2, integer3);
			break;
	case 4:
			integer1 = (rand()%9)+1;
			integer2 = (rand()%99)+1;
			integer3 = (rand()%9)+1;
			operand1 = (rand()%4);
			operand2 = (rand()%4);
			switch(operand1)
			{
			case 0:
				char_op1 = '+';
				break;
			case 1:
				char_op1 = '-';
				break;
			case 2:
				char_op1 = 'x';
				break;
			case 3:
				char_op1 = '/';
				break;
			}
			switch(operand2)
			{
			case 0:
				char_op2 = '+';
				break;
			case 1:
				char_op2 = '-';
				break;
			case 2:
				char_op2 = 'x';
				break;
			case 3:
				char_op2 = '/';
				break;
			}
			printf("Equation %d: %d %c %d %c %d\n\n", (counter+2), integer1, char_op1, integer2, char_op2, integer3);
			break;
	case 5:
			integer1 = (rand()%999)+1;
			integer2 = (rand()%9)+1;
			integer3 = (rand()%9)+1;
			integer4 = (rand()%99)+1;
			operand1 = (rand()%4);
			operand2 = (rand()%4);
			operand3 = (rand()%4);
			switch(operand1)
			{
			case 0:
				char_op1 = '+';
				break;
			case 1:
				char_op1 = '-';
				break;
			case 2:
				char_op1 = 'x';
				break;
			case 3:
				char_op1 = '/';
				break;
			}
			switch(operand2)
			{
			case 0:
				char_op2 = '+';
				break;
			case 1:
				char_op2 = '-';
				break;
			case 2:
				char_op2 = 'x';
				break;
			case 3:
				char_op2 = '/';
				break;
			}
			switch(operand3)
			{
			case 0:
				char_op3 = '+';
				break;
			case 1:
				char_op3 = '-';
				break;
			case 2:
				char_op3 = 'x';
				break;
			case 3:
				char_op3 = '/';
				break;
			}
			printf("Equation %d: %d %c %d %c %d %c %d\n\n", (counter+2), integer1, char_op1, integer2, char_op2, integer3, char_op3, integer4);
			break;
			
	}
	//printf("%c", char_op1);


	real_ans = get_equation(integer1, integer2, integer3, integer4, operand1, operand2, operand3, difficulty);
	
	//printf("%lf\n", real_ans);
	//printf("%d\n%d\n", operand1, operand2);
	
	user_ans = get_answer();
	check = compare_numbers(real_ans, user_ans);
	if(check == 1)
	{
	printf("Good Job! Try another\n");
		switch(difficulty)
	{
		case 1:
			score +=10;
			break;
		case 2:
			score += 50;
			break;
		case 3:
			score += 200;
			break;
		case 4:
			score += 1000;
			break;
		case 5:
			score += 5000;
			break;
	}
	getch();
	}else{
		score -= 50;
	printf("Wrong answer, the answer is %.2lf\n", real_ans);
	getch();
	}
	i++;
	}while(counter<10);
	return score;
}

This code is the main code for the game with other functions around it. However, I cannot figure out how to fine the right answer for the equations that are randomly generated. Does anyone know how I can go about using the appropriate order of operations to do this. For example: say my code randomly generates the equation y = 7 + 2 * 8. How can I tell the computer to compute the 2*8 before the 7+2 but be general enough to compute an equation like 7 / 2 * 8. See what I mean?
Thanks

[quzah]

int doowop( int a, int b, int op ) /* * < / < + < - */
{
   ...
}
...
if( op1 < op2 )
    answer = doowop( doowop( a, b, op1 ) c, op2 )
else
    answer = doowop( a, doowop( b, c, op2 ), op1 );

That should work.


Quzah.