can someone help me make an int main() program

[wishbone34]

I've gotten help writing out these functions, and i know what they each do individually, but i can't figure out where to start in my main program, i want to enter a string of numbers and operators(+,-,*,/) and have the output be the answer(ex. 12+3- would be (1+2)-3=0, im almost certain my functions are fine, they compile without error, any help would be appreciated

#include "stdafx.h"
#include<iostream>
using namespace std;
 
#define MAX_LENGTH 80
int top_operator=0;
char stack_operator[MAX_LENGTH];
int array_pt=0;
char array[MAX_LENGTH];
unsigned int top_operand=0;
float stack_operand[MAX_LENGTH];
 
// Some code has been removed as per FAQ policy
 
int main()
{
   return 0;
}

[Ganon11]

You'll have to get user input - probably character-by-character - and separate it into numbers, operators, etc. From there, you can use your functions depending on what input you get.

You should write (or find) functions that will determine if a character is a number, and a function that will determine if a character is an operator.

[wishbone34]

hi, i'm almost certain all of these functions are correct and will do what I want them to do, however, i am having trouble with the main program and am having trouble making the functions interact with one another......what i want to do is, be able to enter a string(ex. 1+2*3) and have the output be(7). any help would be appreciated!

#include "stdafx.h"
#include<iostream>
using namespace std;
 
#define MAX_LENGTH 80
int top_operator=0;
char stack_operator[MAX_LENGTH];
int array_pt=0;
char array[MAX_LENGTH];
unsigned int top_operand=0;
float stack_operand[MAX_LENGTH];
 
//-------------------------------------------
 
<code snipped as per posting guidelines>
 
void infixTopostfix(char *str)
{
    char *input_string=str;
    char ch;
 
 
    push('(');
    strcat(input_string, ")");
 
    while(*input_string)
    {
        switch(*input_string)
        {
        case '+':
        case '-':
        case '*':
        case '/':
            while(1)
            {
                char top_char=top();
                if(top_char=='\0')
                {
                    cout<<"Invalid expression"<<endl;
                    exit(0);
                }
                else
                if (isOperator(top_char))
    {
    if(precedence_level(top_char)>=precedence_level(*input_string))
        array[array_pt++]=pop();
            else
            break;
    }
    else 
    break;
            }
        }
    }
    push(*input_string);
}
//----------------------------------------------------------------------------------
 
 
 
 
 
 
int _tmain(int argc, _TCHAR* argv[])
{
char token[10];
 
cout<<"Enter string"<<endl;
cin>>token;
infixTopostfix(token);
evaluatePostfixExpr();
cout<<evaluate();
 
 
 
 
    return 0;
}
 

[lqdeffx]

just to help everyone out don't forget to put code inside code tags.

<snipped>
 

[Extremist]

what exactly is the problem?

This is what I can give you:

int main(int argc, char* argv[])
{
    char token[10];
 
    cout<<"Enter string"<<endl;
    cin>>token;
    infixTopostfix(token);
    evaluatePostfixExpr();
    cout<<evaluate();
    return 0;
}
 

Don't forget the code tags, you're just annoying everyone if you forget

[Banfa]

Please read the Posting Guidelines and particularly the Coursework Posting Guidlines.

So far you have posted your full code twice forcing us to edit it twice and double posted your question.

Please post within the posting guidelines.


I do not believe that you do know what each of your functions individually do, specifically I do not believe that you know what infixTopostfix does or you would not attempt to call it in the way you have. Passing "1+2*3" to infixTopostfix causes the program to enter an infinite loop which is what you suggest you do from your text and the way you have written main.

However I know you haven't actually tried your program and examined the output or what it does when it runs because the code you posted does not even compile.

If you understand each function then it should not be a great leap to working out how to call them, so I suggest to clue us in on how you think each function works at which point we may be able to explain to you the part you are mis-understanding.

Banfa
Administrator