36 lines
1.1 KiB
C++
36 lines
1.1 KiB
C++
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// lotto.cpp -- probability of winning
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#include <iostream>
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// Note: some implementations require double instead of long double
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long double probability(unsigned numbers, unsigned picks);
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int main()
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{
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using namespace std;
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double total, choices;
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cout << "Enter the total number of choices on the game card and\n"
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"the number of picks allowed:\n";
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while ((cin >> total >> choices) && choices <= total)
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{
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cout << "You have one chance in ";
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cout << probability(total, choices); // compute the odds
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cout << " of winning.\n";
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cout << "Next two numbers (q to quit): ";
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}
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cout << "bye\n";
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// cin.get();
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// cin.get();
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return 0;
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}
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// the following function calculates the probability of picking picks
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// numbers correctly from numbers choices
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long double probability(unsigned numbers, unsigned picks)
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{
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long double result = 1.0; // here come some local variables
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long double n;
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unsigned p;
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for (n = numbers, p = picks; p > 0; n--, p--)
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result = result * n / p ;
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return result;
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}
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