如何讓這個功能運行多次？

Question

讓我首先注意到我是C++的絕對BEGINNER。所以，請放輕鬆點我。

我一直在寫下面的代碼，作爲今年夏天編程方法課程的一部分。這意味着銀行計劃會根據用戶輸入來計算月數（n），利率（i）和用戶貸款的每月支付。然後，該程序應該從用戶處收取一筆付款金額並計算新的餘額。從這裏，它應該打印一份攤銷報告，描述期初餘額，利息支付，主要付款和期末餘額。所有這些工作都很好，但接下來我遇到了麻煩。該程序應該能夠進行多次付款併爲攤銷報告添加額外的行，並且我無法弄清楚如何再次運行「付款」功能以獲得這些額外付款。請幫助！！

此外，我知道爲成員函數設置的參數幾乎是不需要的，因爲它們被用戶輸入替換，但是它們是指導者在賦值指令中所要求的。

再次感謝您給予的任何建議！

#ifndef LOAN_DATA_H 
#define LOAN_DATA_H 

class Loan_Data 
{ 
private: 
    double Bal; 
    double n; 
    double i; 
    double A; 
     double p; 

public: 
      Loan_Data(double p, double n, double i); 
    void MakePayment(double pay); 
    void PrintAmortizationSchedule(); 
}; 

#endif /* LOAN_DATA_H */ 




#include <cstdlib> 
#include <cmath> 
#include <iostream> 
#include "Loan_Data.h" 

using namespace std; 


Loan_Data::Loan_Data(double p, double n, double i) 
{ 
    cout << "Enter the loan amount: $"; 
    cin >> this->p; 
    cout << "Enter the loan length: "; 
    cin >> this->n; 
    cout << "Enter your credit score: "; 
    cin >> this->i; 

    this->i = this->i/100; 
    this->i = this->i/12; 
    this->n = this->n * 12; 
    Bal = this->p; 
    A = (this->p * ((this->i * pow(1 + this->i, n))/(pow(1 + this->i, n) - 1))); 

    cout << "A is: " << A << endl; 
    cout << "Bal is: " << Bal << endl; 
    cout << "i is: " << this->i << endl; 
} 
void Loan_Data::MakePayment(double pay) 
{ 
    cout << "i is: " << i << endl; 
    cout << "Bal is: " << Bal << endl; 
    cout << "Enter payment first payment amount: $"; 
    cin >> pay; 

    cout << "Bal is: " << Bal << endl; 

    Bal = ((i + 1) * Bal) - pay; 
     A = pay; 
} 

void Loan_Data::PrintAmortizationSchedule() 
{ 
    double iP = (i * Bal); 
    double pP = (A - (i*Bal)); 
    double endingBalance = ((1 + i)*Bal - A); 
    double payment2 = (i + 1)*Bal; 

    cout << "Beginning Bal." << "\t""\t" << cout << "Interest paid" << "\t""\t" << cout << "Principle paid" << "\t""\t" << cout << "Ending Bal." << "\t""\t" << endl; 

    if ((i + 1)*Bal > A) 
    { 
     cout << p << "\t""\t""\t""\t" << iP << "\t""\t""\t""\t" << pP << "\t\t""\t""\t" << endingBalance << endl; 
     endingBalance = Bal; 
    } 
    else if (Bal < A) 
    { 
     cout << Bal << "\t""\t""\t""\t" << iP << "\t""\t""\t""\t" << (payment2 - (i*Bal)) << "\t\t""\t""\t" << ((1 + i)*Bal - payment2) << endl; 
     Bal = ((1 + i)*Bal - payment2); 
    } 
    else if (Bal == 0) 
    { 
     cout << "0" << "\t""\t""\t""\t""\t" << "0" << "\t""\t""\t""\t""\t" << "0" << "\t\t""\t""\t""\t" << "0" << endl; 
    } 

} 

int main(int argc, char *argv[]) 
{ 
    double Bal; 
    double p; 
    double n; 
    double i; 
    double pay; 
    double A; 


    Loan_Data loan1(p, n, i); 

    loan1.MakePayment(pay); 

    loan1.PrintAmortizationSchedule(); 

    return 0; 

} 

Answer 1

修改你的主要使用do while循環 -

int main(int argc, char *argv[]) 
{ 
char ch='n'; 
do { 
double Bal; 
double p; 
double n; 
double i; 
double pay; 
double A; 
Loan_Data loan1(p, n, i); 
loan1.MakePayment(pay); 
loan1.PrintAmortizationSchedule(); 
printf("Do you want to continue "); 
ch=getchar(); 
}while(ch=='y'); 
return 0; 

} 

do while循環重複你的代碼，同時在條件爲真即是封閉的，如果用戶在1日結束時進入ÿ程序將繼續，否則它會退出。

Answer 2

如果你想使一段代碼運行不止一次根據「條件」多，然後用c++ while loop或c++ for loop.

while(condition){ 
execute function; 
} 
for(variable; condition; variable modification){ 
execute function; 
}