Lesson 3: Working with Libraries, and calculating interest

[spoiler title=”Lesson Video”]
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[spoiler title=”Lesson Source Code”]

#include <iostream>
#include <cmath>
using namespace std;
 
 
int main(){
 
  // 1 + 3
  // i + j
  // +, -, *, /, %    -- % is remainder 10%3   10/3 then give me the remainder,  1
  //a, b ,c.   total = a+b+c;   total = 10;  total = total+a+b+c;  total += a+b+c;
  // +=, -=, *=, /=
 
  //Homework: Creating a simple interest calculator -- futureMoney = principle*(rate*time);
  //Creating a compound interest calculator
 
  int years = 0;
  double APR = 0.0, principal = 0.0, total = 0.0;
 
  cout < < "Enter your starting capital: ";
  cin >> principal;
 
  cout < < "\nEnter your APR (ex: 8.0% = 8):  ";
  cin >> APR;
 
  cout < < "\nHow many years will your invest this money for: ";
  cin >> years;
 
  APR /= 100;
  total = principal * (  pow((1+APR),years)  );
  cout < < "\nThe amount in your account after: " << years << " years will be: " << total << endl;
 
 
 
 
  system("PAUSE");
  return 0;
}

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Homework is described and should be submitted here: http://beginnerscpp.com/forums/index.php/topic,55.0.html



Cmath
Cmath is a library that is used to perform mathematical functions in C++ programs. You could always create functions of your own to perform the tasks in this library (when you learn functions down the line). For a more complete listing of functions available inside the cmath library click here


Raising a number to a power
Raising a number to a power is very easy in C++ using the Cmath library. The reference linked above should show you examples. For powers you would use pow(number, powerRaisedTo); as your command.