setw无法正常工作

Question

Im writing a loan amortization program but when I use "setw" to set up my columns its putting "month" and "Current Balance" together and not spacing the others like I want.

I included a picture below of the output on the terminal.

cout << "Month" // sets up columns
     << setw(15) << "Current Balance"
     << setw(15) << "Interest"
     << setw(15) << "Payment"
     << setw(15) << "New Balance \n" << endl;


int month_count = 1;
while( month_count <= number_of_months) // Loops while calculating the monthly interest and new balances produced after payments.
    {
    cout << month_count
         << setw(15) << loan_amount;

    double interest = loan_amount * monthly_rate;

    cout << setw(15) << interest
         << setw(15) << payment;

    loan_amount = loan_amount + interest - payment;

    cout << setw(15) << loan_amount << endl;

    month_count++;
    }

OUTPUT

Answer 1

I'd suggest a few things:

1st: Increase your width to something slightly longer than the maximum width of your column names. In this case you have "Current Balance" which is 15 characters long, so if you use 15 as your field width, you won't get spacing around that column.

2nd: Use std::setw together with std::left for your first column to space our that column too. ( std::left will left-justify the first column)

3rd: Use std::setw together with std::right for your value columns to right align the values, and use a combination of std::fixed and std::setprecision(2) to always print 2 decimal places for your dollar/cent amounts, which makes it easier to read

Here is an example:

#include <iostream>
#include <iomanip>

using namespace std;

int number_of_months = 3;
double loan_amount = 50;
double monthly_rate = 2.3;
double payment = 10;

int main()
{
    cout << setw(7)  << std::left << "Month" // sets up columns
         << setw(17) << std::right << "Current Balance"
         << setw(17) << std::right << "Interest"
         << setw(17) << std::right << "Payment"
         << setw(17) << std::right << "New Balance" << '\n' << endl;


    int month_count = 1;
    while( month_count <= number_of_months) // Loops while calculating the monthly interest and new balances produced after payments.
    {
        cout << setw(7) << std::left << month_count
             << setw(17) << std::right << std::setprecision(2) << std::fixed << loan_amount;

        double interest = loan_amount * monthly_rate;

        cout << setw(17) << std::right << std::setprecision(2) << std::fixed << interest
             << setw(17) << std::right << std::setprecision(2) << std::fixed << payment;

        loan_amount = loan_amount + interest - payment;

        cout << setw(17) << std::right << std::setprecision(2) << std::fixed << loan_amount << endl;

        month_count++;
    }

    return 0;
}

Output:

Month    Current Balance         Interest          Payment      New Balance

1                  50.00           115.00            10.00           155.00
2                 155.00           356.50            10.00           501.50
3                 501.50          1153.45            10.00          1644.95