why am i getting a massive number

[ColeMilla]

Well title says it all, everytime i execute this program i get a MASSIVE number (like 4.95066e-324) , i dont know where im going wrong. please take a look at my code and pseudocode that was provided for me.

// Start
// Declarations
// num amount
// num newAmount
// num interestRate
// output "Please enter the dollar amount. "
// input amount
// output "Please enter the interest rate(e.g., nine percet should beentered as 9.0). "
// input interestRate
// newAmount = FutureValue(amount,interestRate)
// output "The new dollar amount is ", newAmount
// Stop
//
//
//
// num FutureValue(num initialAmount, num interestRate)
// Declarations
// num finalAmount
// finalAmount = (1 + interestRate/100) * initialAmount
// return finalAmount

#include <iostream>
#include <string>

using namespace std;


int main() {
	
	double amount;
	double interestrate;
	double newamount;
	
	
	cout << "please enter the dollar amount.  " << endl;
	cin >> amount;
	cout << "Please enter the interest rate(e.g., nine percet should be entered as 9.0).   " << endl;
	cin >> interestrate;
	double futurevalue(double initialamount, double interestrate);
	cout << "The new dollar amount is " << newamount;
	
	return 0;
}

double futurevalue(double initialamount, double interestrate) {
	
double finalamount;
finalamount = (1 + interestrate/100) * initialamount;

return finalamount;
}

[Peter87]

4.95066e-324 is not a massive number. It means 4.95066 × 10^-324. That's very close to zero.

The problem is that newamount is not initialized.

[ColeMilla]

oh my goodness im dumb haha, how would i go about doing that? declaring it ? or just switching it out for finalamount? my instructor wrote the psuedocode and it just doesnt seem right.

[Ganado]

Look at the comments of your original post

// newAmount = FutureValue(amount,interestRate)

You need to actually call your futurevalue function from main.
http://www.cplusplus.com/doc/tutorial/functions/

[seeplus]

L18 is a function declaration (prototype). These are usually placed after any #includes not in the middle of code. I suspect you mean to call the function here as per the appropriate comment.

[keskiverto]

We can look at you code and ask: where are 'newamount'? Only on lines 11 and 19:

double newamount;
cout << "The new dollar amount is " << newamount;

The first is a declaration, but it does include initializer. Here are examples of initialization:

double newamount {};  // sets value to 0.0
double newamount {3.14};  // sets value to 3.14
double newamount = FutureValue(amount,interestRate); // sets value to whatever the FutureValue returns 

Your second line reads the current value of 'newamount'. Alas, the value was never set.

[seeplus]

but it does include initializer

???

[keskiverto]

According to https://en.cppreference.com/w/cpp/language/declarations
int answer {42} ; is a declaration

int is decl-specifier-seq

answer {42} is init-declarator

answer is declarator

{42} is initializer that performs direct initialization. The initializer is optional.

[seeplus]

@keskiverto - I took your words to mean that double newamount; is a declaration and also an initializer which, of course, isn't right as there's no initializer. I see now that you meant that initializer was optional. Sorry :)