#include <iostream>

#include <iomanip>

#include <string>

#include <math.h>

#include <windows.h>

//set namespace to eliminate the need for std:: prefixes

using namespace std;

//public defines

int runloan();

bool isvalidnumber(string * puserinput);

void printheader(int iPrintYear);

HANDLE hConsole = GetStdHandle(STD_OUTPUT_HANDLE); //get handle to standard output

int main()

{

//set color of output to intense white text with standard black background

SetConsoleTextAttribute(hConsole, 15 | 1);

//set default first run to yes so loan procedure runs with out prompt

string userinput = "Y";

//loop while variable is Y allong user to input choices

while (strcmp(userinput.c_str(),"Y") == 0)

{

runloan(); //run the main loan routine

userinput = "";

//loop till user enters Y or N

while (strcmp(userinput.c_str(), "Y") != 0 && strcmp(userinput.c_str(), "N") != 0)

{

cout << "Do you want to restart the program? (Y or N): ";

getline(cin, userinput);

//convert first letter user input to upper case if single letter was entered only

if (userinput.length() == 1)

{

      userinput = toupper(userinput[0]); //convert first letter to upper case

}

}

}

return 0;

}

int runloan()

{

string userinput;

double amount, rate, term, payment, interest, principle;

int iCounter=0, iYear=1, loanchecker;

string * puserinput = &userinput; // pointer to user input variable

//formatting output with a decimal place of 2

cout << setiosflags(ios::fixed | ios::showpoint) << setprecision(2);

//get loan amount routine

userinput = "";

//loop till valid numeric number is found and is not empty

while(!isvalidnumber(puserinput) || userinput.length() == 0)

{

      cout << "Enter the amount of loan: ";

      getline(cin, userinput);

}

amount = atof(userinput.c_str()); //convert string to double

loanchecker = (int)amount;

//get interest rate routine

userinput = "";

//loop till valid numeric number is found and is not empty

while(!isvalidnumber(puserinput) || userinput.length() == 0)

{

      cout << "Enter the interest rate: ";

      getline(cin, userinput);

}

rate = atof(userinput.c_str()); //convert string to double

//if rate is a not a decimal convert value to decimal

if(rate > 1)

      rate = (rate/100);

//get term routine

userinput = "";

//loop till valid numeric number is found and is not empty

while(!isvalidnumber(puserinput) || userinput.length() == 0)

{

      cout << "Enter the total number of years: ";

      getline(cin, userinput);

}

term = atof(userinput.c_str()); //convert string to double

//calculate the monthly payment

payment = (amount * pow((rate / 12) + 1, (term * 12))* rate / 12)/(pow(rate / 12 + 1, (term

* 12)) - 1);

//output loan specific data header information

cout << "\nUser Specified Loan Details" << endl;

cout << setfill('-') << setw(80) << "-" << endl;

//output report hearder information

printheader(iYear);

//output the monthly payment

while (loanchecker != 0)

{

//increment counters

iCounter++;

//calculate interest rate based on remaining loan amount

interest = (amount * rate) / 12;

//calculate new loan amount after payment plus interest

amount = (amount - payment) + interest;

//calculate principle by subtracting the interest

principle = payment - interest;

loanchecker = (int)amount;

//prevent a negative number once loan is paid off

if (loanchecker == 0) amount = 0;

//output loan information for a specific month

cout << iCounter << "\t" << payment << "\t\t" << interest << "\t\t" << principle <<

"\t\t" << amount << endl;

//allow screen data to be buffered if the loan amount is not 0 per year

if (iCounter == 12 && amount != 0)

{

iCounter = 0;

iYear++;

cout << "Press enter to continue...";

getline(cin, userinput);

//output report header information

printheader(iYear);

}

}

return 0;

}

bool isvalidnumber(string * puserinput)

{

bool decimal = true;

string checkstring = *puserinput; //convert memory location to string

for(int count=0; count < (int)checkstring.length(); count++) //loop the char array for invalid numeric data

{

if(isdigit(checkstring[count]) || checkstring[count] == '.' && decimal == true)

{

if(checkstring[count]== '.') //only allows one decimal place

{

decimal = false;

}

}

else

{

return false; //numeric validation failed

}

}

return true; //numeric validation success

}

void printheader(int iPrintYear)

{

//clear screen

system("cls");

//set color of output

SetConsoleTextAttribute(hConsole, 12);

//output current reporting year

cout << "\nDetails for year: " << iPrintYear << endl;

//set color of output

SetConsoleTextAttribute(hConsole, 14);

//output loan payment specific data header information

cout << "Month\tPayment\t\tInterest\tPrinciple\tLoan Amount" << endl;

cout << setfill('-') << setw(80) << "-" << endl;

//reset color of output to initial color text

SetConsoleTextAttribute(hConsole, 15);

}