Setting String equal to char array?

May I recommend structuring the linked list code into functions.

Anyway, there's no reason to make the list doubly linked. Your assignment says that you need a stack and a queue implemented as linked lists. All you need is a linked list where you can push a new value onto either end, and the ability to read and pop one end.

I got the equations to get inserted into the linked list. Now I will work on making the code easier to read. I was initially thinking of making the doubly linked list because input members in the stack would be inserted in reverse order. But I ended up making another stack(making stacks were a little more simple than making a queue although a bit more inefficient) which copied in the data from the first stack. Now when I print what I enter, it is in the correct order. Here is my current working code, I will modify it in due time.

Here is the code:

Code:

#include <iostream>

using namespace std;

struct node
{
float num;
char opr;
char type;
node* next;
node* prev;
};

void printList(const node*);
//entry* insert(int n, node* h);
//entry* deleteNode(int n, node* h);
//entry* PQInit(entry* h, entry* PQh);
float arrayToFloat(char part[]);

int main()
{
node *temp = 0, *head = 0;//starts out empty
node *PQt = 0, *PQh = 0, *PQp = 0;//Polish queue
float fltval;
int j, n = 0, flag, count = 0;
char string[80];

	cout << "Enter an algebraic equation in reverse polish notation: \n";
	cin.getline(string, 80);

	cout << "Output from func arrayToInt:\n";
	while(string[n] != '\0')
	{
	char part[15] = {'O'};

		for(j = 0, flag = 0; (string[n] != ' ') && (string[n] != '\0'); j++, n++) 
		{
			part[j] = string[n];
			if(!isdigit(part[j]))//if character
			{
				flag = 1;
			}//if
		}//for
		n++;

		if(flag == 0)//if part consists of int
		{
			if(string[n] != '\0')
			{
				fltval = arrayToFloat(part);//converting array based number to float
				cout << fltval << endl;

				head = new node;
				head->num = fltval;
				head->type = 'N';
				head->next = temp;
				temp = head;
			}//if
		}//if
		else
		{
			if(string[n] != '\0')
			{
				head = new node;
				head->opr = part[0];
				head->type = 'O';
				head->next = temp;
				temp = head;
			}//if
		}//else

	}//while

	//PQh = PQInit(head, PQh);
	cout << "Output from linked list:\n";
	printList(head);

	//creating PQ stack from initial array
	while(head != 0)
	{
		PQh = new node;
		if(head->type == 'N')
		{
			PQh->num = head->num;
			PQh->type = 'N';
			PQh->next = PQt;
			PQt = PQh;
		}//if
		else
		{
			PQh->opr = head->opr;
			PQh->type = 'O';
			PQh->next = PQt;
			PQt = PQh;
		}//else

		head = head->next;
	}//while

	cout << "Output from PQ: \n";

	printList(PQh);

	return 0;
}//main

/***************************************/
//Prints list of Nodes

void printList(const node* pointer)
{
	while(pointer != 0)
	{
		if(pointer->type == 'N')
			cout << pointer->num << " ";
		else
			cout << pointer->opr << " ";

		pointer = pointer->next;
	}//while
	cout << endl;

}//printList

/****************************************/
//Converts an array of ints to a float value

float arrayToFloat(char part[])
{
int L = 0, i, j;
float val = 0, value[15] = {0};
float valtab[5] = {1, 10, 100, 1000, 10000};
//                 1   2   3     4     5

	for(i = 0; part[i]; i++)
	{
		value[i] = part[i] - '0';//converting to int from char	
	}//for
	
	L = strlen(part);
	for(i = 0, j = L - 1; i < L; i++, j--)
	{
		val = val + (value[i] * valtab[j]);
	}//for

	return val;
}//arrayToFloat

When I originally started working on making the second stack, I was working on it in a separate function, but I got a ton of errors and just decided to get it working first in main. Just be ware this is very dated function, I am better off copying what I have in main into the function rather than this. I am posting this so you guys can see if I did anything wrong and so you can correct me before I update this function. Any tips to help me with this will be appreciated. Here is the (commented out) function code:

Code:

/******************************************/
//Initializes PQ
/*
entry* PQInit(entry* h, entry* PQh)
{
node* head = h;

	while(h->next != 0)
	{
		if(h->type == 'N')
			PQh->num = head->num;
		else
			PQh->opr = head->opr;

		head = head->next;
		PQh = PQh->next;
		
	}//while
	return h;
	
}//PQInit
*/

Thanks for all your help!