Anyone care to proof-read my code?
Well, I finished up my project... one week early too! So I figured I'll post it here and perhaps someone could blow a whistle and tell me of some things I could do to improve it! :D
Basically, the program reads in a file with a single equation, in postix form, and solves it.
I basically used a linked list implementation of a stack (because I wanted to, dammit! :D ), but it would be nice if I could think of a way to pass one parameter to pop(*node, *node) rather than 2.
Any other comments (memory leaks, inefficeincy, insults, etc.) are welcomed, and the code is released for public use under the GPL.
Code:
#include <iostream.h>
#include <stdio.h>
#include <fstream.h>
#include <cstring>
struct node
{ int key; struct node *next;};
typedef node* stack_ptr;
void push(stack_ptr& a_stack, int number);
void print_list(stack_ptr& a_stack, stack_ptr& b_stack);
int pop(stack_ptr& a_stack,stack_ptr& b_stack);
main()
{
char inFileName[16], str1[50];
int n, v, total=0;
struct node *t, *x;
ifstream read;
/* initialize the list */
t = new node;
t->next = NULL;
x = t;
/****** Ask user for input file *****/
cout <<"Enter file name to be read: ";
cin >> inFileName;
/***** open file **********/
read.open(inFileName);
if (read.fail())
{
cout << "Input file opening failed!"<<endl;
exit(1);
}
/*********************************************************
* Read file for digits and operators
* (it is assumed there are no illegal chars in the file
*********************************************************/
for (int i = 0; !read.eof(); i++)
{
read.getline(str1,50, ' ');
if (isdigit(str1[0]))
{
v = atoi(str1);
push(t, v);
}
else if (str1[0] == '+')
{
v = pop(t, x) + pop(t,x);
push (t, v);
}
else if (str1[0] == '-')
{
v = pop(t, x) - pop(t,x);
push (t, v);
}
else if (str1[0] == '*')
{
v = pop(t, x) * pop(t,x);
push (t, v);
}
else if (str1[0] == '/')
{
v = pop(t, x) / pop(t,x);
push (t, v);
}
}
/****************************************************
* Now print all the numbers left in the linked list
* which should only be one left if correct postfix
* notation was used in the input file.
****************************************************/
print_list(t, x);
return 0;
}
void push(stack_ptr& a_stack, int number)
{
a_stack->next = new node;
a_stack->next->next = NULL;
a_stack->key = number;
a_stack = a_stack->next;
}
void print_list(stack_ptr& a_stack, stack_ptr& b_stack)
{
if (b_stack->next == NULL)
{
cout << "The stack is currently empty! "<<endl;
}
else
{
a_stack = b_stack;
do
{
if (a_stack->next != NULL)
cout << a_stack->key << " ";
a_stack = a_stack->next;
}while(a_stack->next != NULL);
cout << endl;
}
}
int pop(stack_ptr& a_stack,stack_ptr& b_stack)
{
int rtn_value = 0;
if (b_stack->next == NULL)
{
cout << "The stack is currently empty! "<<endl;
}
else
{
a_stack = b_stack;
while(a_stack->next->next != NULL)
a_stack = a_stack->next;
rtn_value = a_stack->key;
delete a_stack->next;
a_stack->next = NULL;
}
return rtn_value;
}
