Currency Formatting in C++

Question

I have been having a really hard time trying to get my code to work properly. I need to write a program that takes a number no bigger than 12 digits and converts it into currency format using string manipulation. I feel like I have most of it but I don't know how to get the - sign to be in front of the $ sign and how to get the commas to work when there is no decimal at the end.

Here it is:

/*
    I need a 12 digit maximum double precision number

        verify that it is a double < 12 digits
        verify that all digits are numeric with a possible
        minus sign in the first position t
        decimal is 2nd or 3rd last digit;

    convert the number to currency using string manipulation
        with commas placed at 3 digit intervals counted from the decimal
        $ in front
        - in front of $
        0 is a positive number

    Display currency format
    */
#include <iostream>
#include <string>


using namespace std;

void dollarFormat(string &);

int main()

{
    cout << "Student Name: \t Chad Weireter" << endl
        << "Student ID:900658044" << endl << endl;

    string input;

        cout << "Please enter a number up to 12 digits long." << endl
            << "The number may be positive or negative" << endl
            << "and may include fractions (Up to two decimal positions)" << endl
            << "Sign and decimal dot(.) are not included in the digit count: ";

        cin >> input;
        dollarFormat(input);
        cout << "The currency value is:\t" << input << endl;

        cin.get();
        cin.ignore();

}

void dollarFormat(string &currency)
{
    int dp;
    dp = currency.find('.');
    if (dp > 3)
    {
        for (int x = dp - 3; x > 0; x -= 3)
            currency.insert(x, ",");
    }
    currency.insert(0, "$");

}

Answer 1

Minus Sign

For the minus sign... have you considered doing what you did with the find('.') ?

try doing find('-') .

What index position will the minus sign be in if its a negative number?

Next, if there is a minus sign at that index then should you be inserting the dollar sign at the 0 index... or should you be inserting it somewhere else?

Dollar Sign

When you insert the dollar sign... you need to make a decision here with a control statement... if positive number then insert the dollar sign at index 0 (like you did already)... else negative insert the dollar sign at index position... :)