simulating a payment structure

[Adasuna]

Hello I am currently stuck on this code, it doesn't display the list and when I do change one code it endlessly loop.

#include <iostream>
   #include <iomanip>
  
   using namespace std;
  
   int main()
   {
       double balance, monthly, apr, apr_monthly, start_bal, interest, end_bal;
       int months = 0;
      cout << fixed << setprecision(2);
 
      cout << "What is the outstanding balance? ";
     cin >> balance;
      cout << "What is the APR? ";
      cin >> apr;
 
     do
      {
 
          start_bal = balance;
          cout << "How much do you pay every month? ";
          cin >> monthly;
 
         cout <<"\n\nThe table shows how long it will take to pay:\n\n";
 
           if( monthly < 0)
              {
                 cout << "How much do you pay every month? ";
                  cin >> monthly;
             }
 
         while( start_bal > 0)
          {
             apr_monthly = (apr/12)/100;
             interest = start_bal*apr_monthly;
             end_bal = start_bal + interest - monthly;
 
             months++;
 
              if(start_bal > monthly)
              {
                 cout << setw(5) << months << setw(10) << start_bal << interest
                      << setw(10) << apr_monthly << setw(5) << end_bal;
 
                  start_bal = end_bal;
             }
        }
    }while(balance > 0);
      return 0;
}

This is what the output should be

                              What is the outstanding balance? 2000
What is the APR? 24
How much do you pay every month? -10
How much do you pay every month? -100
How much do you pay every month? 125

The table shows how long it will take to pay:

Month	  Start	Interest	Monthly	    End
    1	2000.00	   40.00	 125.00	1915.00
    2	1915.00	   38.30	 125.00	1828.30
    3	1828.30	   36.57	 125.00	1739.87
    4	1739.87	   34.80	 125.00	1649.66
    5	1649.66	   32.99	 125.00	1557.66
    6	1557.66	   31.15	 125.00	1463.81
    7	1463.81	   29.28	 125.00	1368.09 
    8	1368.09	   27.36	 125.00	1270.45
    9	1270.45	   25.41	 125.00	1170.86
   10	1170.86	   23.42	 125.00	1069.27
   11	1069.27	   21.39	 125.00	 965.66
   12	 965.66	   19.31	 125.00	 859.97
   13	 859.97	   17.20	 125.00	 752.17
   14	 752.17	   15.04	 125.00	 642.22
   15	 642.22	   12.84	 125.00	 530.06
   16	 530.06	   10.60	 125.00	 415.66
   17	 415.66	    8.31	 125.00	 298.97
   18	 298.97	    5.98	 125.00	 179.95
   19	 179.95	    3.60	 125.00	  58.55
   20	  58.55	    1.17	 125.00	 -65.28

The entire code cannot have a break in any statement.

[48T7M4Gy]

This might be a start to getting back on track:

#include <iostream>
#include <iomanip>

using namespace std;

int main()
{
    double balance = 0, monthly = 0, apr = 0, interest = 0;
    int months = 0;
    
    cout << fixed << setprecision(2);
    
    cout << "What is the outstanding balance? ";
    cin >> balance;
    
    cout << "What is the APR? ";
    cin >> apr;
    
    cout << "How much do you pay every month? ";
    cin >> monthly;
    
    cout <<"\nThe table shows how long it will take to pay:\n\n";
    
    while( balance > 0)
    {
        cout
        << setw(5) << months << setw(10) << balance << setw(10) << interest << endl;
        
        interest = balance * apr/1200;
        balance = balance + interest - monthly;
        
        months++;
    }
    
    return 0;
}

 0   2000.00      0.00
    1   1915.00     40.00
    2   1828.30     38.30
    3   1739.87     36.57
    4   1649.66     34.80
    5   1557.66     32.99
    6   1463.81     31.15
    7   1368.09     29.28
    8   1270.45     27.36
    9   1170.86     25.41
   10   1069.27     23.42
   11    965.66     21.39
   12    859.97     19.31
   13    752.17     17.20
   14    642.22     15.04
   15    530.06     12.84
   16    415.66     10.60
   17    298.97      8.31
   18    179.95      5.98
   19     58.55      3.60
Program ended with exit code: 0