Julio Biason
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3 years ago | |
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.exercism | 3 years ago | |
HELP.md | 3 years ago | |
HINTS.md | 3 years ago | |
InterestIsInteresting.cs | 3 years ago | |
InterestIsInteresting.csproj | 3 years ago | |
InterestIsInterestingTests.cs | 3 years ago | |
README.md | 3 years ago |
README.md
Interest is Interesting
Welcome to Interest is Interesting on Exercism's C# Track.
If you need help running the tests or submitting your code, check out HELP.md
.
If you get stuck on the exercise, check out HINTS.md
, but try and solve it without using those first :)
Introduction
Floating Point Numbers
A floating-point number is a number with zero or more digits behind the decimal separator. Examples are -2.4
, 0.1
, 3.14
, 16.984025
and 1024.0
.
Different floating-point types can store different numbers of digits after the digit separator - this is referred to as its precision.
C# has three floating-point types:
float
: 4 bytes (~6-9 digits precision). Written as2.45f
.double
: 8 bytes (~15-17 digits precision). This is the most common type. Written as2.45
or2.45d
.decimal
: 16 bytes (28-29 digits precision). Normally used when working with monetary data, as its precision leads to less rounding errors. Written as2.45m
.
As can be seen, each type can store a different number of digits. This means that trying to store PI in a float
will only store the first 6 to 9 digits (with the last digit being rounded).
While Loops
In this exercise you may also want to use a loop. There are several ways to write loops in C#, but the while
loop is most appropriate here:
int x = 23;
while (x > 10)
{
// Execute logic if x > 10
x = x - 2;
}
Do While Loops
An less commonly used alternative to the above syntax is a do-while
loop:
int x = 23;
do
{
// Execute logic if x > 10
x = x - 2;
} while (x > 10)
Instructions
In this exercise you'll be working with savings accounts. Each year, the balance of your savings account is updated based on its interest rate. The interest rate your bank gives you depends on the amount of money in your account (its balance):
- -3.213% for a negative balance.
- 0.5% for a positive balance less than
1000
dollars. - 1.621% for a positive balance greater or equal than
1000
dollars and less than5000
dollars. - 2.475% for a positive balance greater or equal than
5000
dollars.
You have three tasks, each of which will deal your balance and its interest rate.
1. Calculate the interest rate
Implement the (static) SavingsAccount.InterestRate()
method to calculate the interest rate based on the specified balance:
SavingsAccount.InterestRate(balance: 200.75m)
// 0.5f
Note that the value returned is a float
.
2. Calculate the annual balance update
Implement the (static) SavingsAccount.AnnualBalanceUpdate()
method to calculate the annual balance update, taking into account the interest rate:
SavingsAccount.AnnualBalanceUpdate(balance: 200.75m)
// 201.75375m
Note that the value returned is a decimal
.
3. Calculate the years before reaching the desired balance
Implement the (static) SavingsAccount.YearsBeforeDesiredBalance()
method to calculate the minimum number of years required to reach the desired balance:
SavingsAccount.YearsBeforeDesiredBalance(balance: 200.75m, targetBalance: 214.88m)
// 14
Note that the value returned is an int
.