Thread: Help altering code to work with char array

I'm writing code for an assignment for infix to postfix conversion using stack class and queue class. My conversion function I think needs to accept a character array, but I have set up in main to get a line from the file that is the infix to be converted. It is currently getting this line and treating it like a string, and I think if I switch the code to retrieving the infix as a character array instead of a string, things will move along. I'm not quite sure what to do though :-(

If I declare Next as string in main, and set the function to accept infix as string, the program compiles and crashes with a Debug Assertion Error, string subscript out of range.

If I set it up how I have in this post, I have errors anywhere I use infix[i] saying subscript requires array or pointer type.

I tried declaring Next as char Next[size]; and then infix in the function as char infix[size] which gave me the error regarding using getline.

Halp! ::banghead::

infix to postfix :

Code:

void infix_to_postfix(char infix)
{
       Stack Stack;
	   Queue Queue;

	   for (int i=0;i<size;i++) {
		   if (infix[i] != '+' || infix[i] != '-' || infix[i] != '*' || infix[i] != '/' || infix[i] != '^') {
			   Queue.Enqueue(infix[i]); //if infix[i] is number, place in queue
		   }//if
		   else if (infix[i] == '(') {
			   Stack.Push(infix[i]);
		   }//else if
		   else if (infix[i] == ')') {
			   while (Stack.Top() != '(') {
				   Queue.Enqueue(Stack.Top());
				   Stack.Pop();
			   }//while
			   Stack.Pop(); //remove ')' from stack
		   }//else if
		   else if (infix[i] == '+' || infix[i] == '-' || infix[i] == '*' || infix[i] == '/' || infix[i] == '^') {
			   while (!Stack.Empty() && order_ops(Stack.Top()) <= order_ops(infix[i])){
				   Queue.Enqueue(Stack.Top());
				   Stack.Pop();
			   }//while
			   Stack.Push(infix[i]);
		   }//else if
	   }//for
}//end infix_to_postfix

main:

Code:

int main(int argc, char *argv[]) {
	char Next;
	ifstream infile("A2.txt");

	while (infile.good()) {
		getline(infile,Next);
		if (infile.good())
			cout << "Infix : \n" << Next << endl;
		infix_to_postfix(Next);
	}//while

	infile.close();

	system("PAUSE");
	return 0;
}

Code:

char Next;

That there's a datatype that will hold one, single character.

Originally Posted by rags_to_riches

Code:

char Next;

That there's a datatype that will hold one, single character.

Right. So I thought about using char Next[size] and in the infix to postfix function setting the input as char infix[size] so it would hold the length that I need. But I run into an error with using getline: error C2784 ... could not deduce template argument for 'std::basic_istream<_Elem,_Traits> &' from 'std::ifstream'

Would I be able to use strcpy to convert Next to char array like this?

Code:

string Next;
char Next2[size];
ifstream infile("A2.txt");

while (infile.good()) {
	getline(infile,Next);
	strcpy(Next2, Next.c_str());
	if (infile.good())
		cout << "Infix : \n" << Next2 << endl;
	infix_to_postfix(Next2);
}//while

Would I then be able to pass Next2 as char to the infix_to_postfix function as the infix?

Code:

void infix_to_postfix(char infix[size])