CODEWITHSUNDEEP
c++if-statementcomparison
Flip
Flip

Reputation: 45

Trouble in a program to convert between currencies in C++

I've made a simple program in C++ to convert between currencies, as part of a lesson. It asks for a numerical value and then a letter (y, e or p) to represent one of the supported currencies. When using 'y' or 'p' you can input the numerical value and character together or separated by a space (ie: "100y" or "100 y") and it'll work fine. However, for the letter 'e' only, if I enter both together, it doesn't recognize as a valid input. Does anyone have any idea why?

Here's the code: 

#include <iostream>

int main()
{
using namespace std;
constexpr double yen_to_dollar = 0.0081;    // number of yens in a dollar
constexpr double euro_to_dollar = 1.09;     // number of euros in a dollar
constexpr double pound_to_dollar = 1.54;    // number of pounds in a dollar

double money = 0;                           // amount of money on target currency
char currency = 0;
cout << "Please enter a quantity followed by a currency (y, e or p): " << endl;
cin >> money >> currency;

if(currency == 'y')
    cout << money << "yen == " << yen_to_dollar*money << "dollars." << endl;
else if(currency == 'e')
    cout << money << "euros == " << money*euro_to_dollar << "dollars." << endl;
else if(currency == 'p')
    cout << money << "pounds == " << money*pound_to_dollar << "dollars." << endl;
else
    cout << "Sorry, currency " << currency << " not supported." << endl;

return 0;
}

Upvotes: 2

Views: 591

Answers (1)

Maciej
Maciej

Reputation: 9595

When you enter 100e10e it works ok. 100e10 is a valid number in scientific notation. 100e is not a valid number in scientific notation. It is not converted to double and money is assigned 0. Variable currency stays unchanged. That is why you get "Sorry, currency not supported" message. e belongs to a number in this case, because it fits scientific notation format.

You could assign 4 chars to every currency( _EUR for instance ) . It would solve the problem and be more user friendly.

Upvotes: 2

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