等额本息,是指一种贷款的还款方式。等额本息是在还款期内,每月偿还同等数额的贷款(包括本金和利息)。
计算公式
每月还款额=[贷款本金×月利率×(1+月利率)^还款月数]÷[(1+月利率)^还款月数-1]
还款公式推导
设贷款总额为M,银行月利率为p,总期数为n(个月),月还款额为x,则各个月所欠银行贷款为:
a[n] =(1 + p)*a[n - 1] - x ;其中a[0]=M
由于还款总期数为n,也即第n月刚好还完银行所有贷款,令a[n]=0,求x:
JAVA实现
import java.util.Scanner;
public class ComputeLoan {
public static void main(String[] args) {
// Create a Scanner
Scanner input = new Scanner(System.in);
// Enter yearly interest rate
System.out.print("Enter yearly interest rate, for example 8.25: ");
double annualInterestRate = input.nextDouble();
// Obtain monthly interest rate
double monthlyInterestRate = annualInterestRate / 1200;
// Enter number of years
System.out.print(
"Enter number of years as an integer, for example 5: ");
int numberOfYears = input.nextInt();
// Enter loan amount
System.out.print("Enter loan amount, for example 120000.95: ");
double loanAmount = input.nextDouble();
// Calculate payment
double monthlyPayment = loanAmount * monthlyInterestRate / (1
- 1 / Math.pow(1 + monthlyInterestRate, numberOfYears * 12));
double totalPayment = monthlyPayment * numberOfYears * 12;
// Display results
System.out.println("The monthly payment is $" +
(int)(monthlyPayment * 100) / 100.0);
System.out.println("The total payment is $" +
(int)(totalPayment * 100) / 100.0);
}
}
run:
Enter yearly interest rate, for example 8.25: 5.5
Enter number of years as an integer, for example 5: 20
Enter loan amount, for example 120000.95: 500000
The monthly payment is $3439.43
The total payment is $825464.76
成功构建 (总时间: 49 秒)