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Prefix function doesn't process numbers with more than one digit correctly

alyuleth (11)
So my prefix takes a char array then get rid of the spaces reverses
it, then processes it. It only works for equations for numbers with single digits like 1 + 2 * 3. If I enter an equation with a double digit number like 10 + 1 it processes 10 as 0 and a 1. I'm not sure why that's happening. I had an idea of using a bool to check if theirs more than one digit but I'm not sure where to apply it.
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void prefix(char * arr)
{
	arr = getRideSpaces(arr);
	cout << "No spaces" << arr << endl;
		arr = reverse(arr);
		cout << arr << endl;
		arr = parenthesisCheck(arr);
		cout << arr << endl;
		stackADT<char> operators;
		QueueADT<char> operands;
		int count = 0;
		int pCount =0, toQueue;
		for (int i = 0; i < strlen(arr); i++)
		{
			switch (arr[i])
			{
			case '(':
				operators.push(arr[i], count);
			
				count++;
				pCount++;
				break;
			case ')':
				toQueue = pCount - 1;
				for (int i = 1; pCount >0; i++)
				{
					cout << "this is pCount\t" << pCount << endl;
					operands.enqueue(arr[i]);
					operators.pop(count - i);
					pCount--;
				}
				count--;

				operators.peek();
				break;
			case '%':
				operators.push(arr[i], count);
				count++;
				if (pCount > 0)
				{
					pCount++;
				}
				break;
			case '*':
				operators.push(arr[i], count);
				count++;
				if (pCount > 0)
				{
					pCount++;
				}
				break;
			case '/':
				operators.push(arr[i], count);
				count++;
				if (pCount > 0)
				{
					pCount++;
				}
				break;
			case '+':
				operators.push(arr[i], count);
				count++;
				if (pCount > 0)
				{
					pCount++;
				}
				break;
			case '-':
				operators.push(arr[i], count);
				count++;
				if (pCount > 0)
				{
					pCount++;
				}
				break;
			}
			if (isdigit(arr[i]))
			{
				operands.enqueue(arr[i]);
			}
		}
		cout << "TESTING THE STACK\n";
		operators.peek();
		cout << "TESTING THE ENQUEUE\n";
		operands.display2();
		//cout<<arr<<endl;
	}
char * parenthesisCheck(char *arr)
{
	for (int i = 0; i < strlen(arr); i++)
	{
		if (arr[i] == '(')
		{
			arr[i] = ')';
		}
		else if (arr[i] == ')')
		{
			arr[i] = '(';
		}
	}
	return arr;
}
char * reverse(char * arr)
{
	char temp;
	int length = strlen(arr);
	for (int i = 0; i < length / 2; i++)
	{
		temp = *(arr + i);
		*(arr + i) = *(arr + (length - (i + 1)));
		*(arr + length - (i + 1)) = temp;
	}
	return arr;
}
char* getRideSpaces(char arr[])
{
	char  *ptr = new char[10];
	
	int i = 0, j = 0;
	while (arr[i])
	{
		if (arr[i] != ' ')
		{
			arr[j++] = arr[i];
		}
		i++;
	}
	//cout << arr[0] << "<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n";

	arr[j] = '\0';
	return arr;
}
Last edited on
Ganado (6812)
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			if (isdigit(arr[i]))
			{
				operands.enqueue(arr[i]);
			}

Well, it looks like you're separately enqueuing each digit, so it sounds like expected behavior to me.

If you have a QueueADT<char>, then you can only put chars in there, not full multi-digit numbers (or at least, not numbers > 255 if you interpret the values correctly).

I would instead have a Queue of ints, and enqueue each integer.
Also, are you allowed to use std::strings?
Last edited on
AbstractionAnon (6954)
Line 117: You have a memory leak. ptr is never deleted. In fact, ptr is never used.
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