The definition of Interest Rate and Compound Interest Rate. *In* this *C++* program to *calculate* simple *interest and Compound Interest Rate*, We define four variables p, t, r, and i which stores principal amount, time, *rate*, and *interest* rate *Using* the *formula* of simple *interest* and compound interest. As the simple interest is calculated by the formula **i=(p* r*t)/100** and the compound interest within the formula is

**ci=(p*pow(1-i,t)-p)**

To work with these calculation in C++, please a new project (visit our previous post How to create a project using C++ programming in Visual Studio. Then using this code below:

```
#include<iostream>
#include<cmath>
using namespace std;
int main()
{
double p, t, r, i, ci;//variables for formulas
// i=(p*r*t)/100 simple interest rate
// ci=(p*pow(1-i,t)-p) compound interest rate
char choice;
cout << "What do you want to look for?\n" << "1. Find Simple Interest Rate.\n" << "2. Find Compound Interest Rate:\n" <<"Please type number 1 or 2"<<endl;
cin >> choice;
switch (choice)
{
case '1': //find simple interest rate
cout << "You are finding simple interest rate" << endl;
cout << "---------------------------------------------" << endl;
cout << "Please enter your pricipal amount:\t";
cin >> p;
cout << "Please enter your loan interest rate:\t";
cin >> r;
cout << "Please your loan period:\t";
cin >> t;
i = (p*t*r) / 100;
cout << "Your simple interest rate is:\t" << i;
break;
case '2':
cout << "You are finding compound interest rate" << endl;
cout << "---------------------------------------------" << endl;
cout << "Please enter your pricipal amount:\t";
cin >> p;
cout << "Please enter your simple interest rate:\t";
cin >> i;
cout << "Please your loan period:\t";
cin >> t;
ci = p*pow(1-i,t)-p;
cout << "Your simple interest rate is:\t" << ci;
break;
default:
cout << "No selection has chosen";
break;
}
system("pause > 0");
}
```

The programming above is using choice as an option for users who can get the their options for choosing whether they want to calculate simple interest or compound interest.