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68 lines
2.4 KiB
68 lines
2.4 KiB
// Copyright 2005, Google Inc. |
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// All rights reserved. |
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// |
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// Redistribution and use in source and binary forms, with or without |
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// modification, are permitted provided that the following conditions are |
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// met: |
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// |
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// * Redistributions of source code must retain the above copyright |
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// notice, this list of conditions and the following disclaimer. |
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// * Redistributions in binary form must reproduce the above |
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// copyright notice, this list of conditions and the following disclaimer |
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// in the documentation and/or other materials provided with the |
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// distribution. |
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// * Neither the name of Google Inc. nor the names of its |
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// contributors may be used to endorse or promote products derived from |
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// this software without specific prior written permission. |
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// |
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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// A sample program demonstrating using Google C++ testing framework. |
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// |
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// Author: wan@google.com (Zhanyong Wan) |
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#include "sample1.h" |
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// Returns n! (the factorial of n). For negative n, n! is defined to be 1. |
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int Factorial(int n) { |
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int result = 1; |
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for (int i = 1; i <= n; i++) { |
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result *= i; |
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} |
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return result; |
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} |
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// Returns true iff n is a prime number. |
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bool IsPrime(int n) { |
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// Trivial case 1: small numbers |
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if (n <= 1) return false; |
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// Trivial case 2: even numbers |
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if (n % 2 == 0) return n == 2; |
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// Now, we have that n is odd and n >= 3. |
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// Try to divide n by every odd number i, starting from 3 |
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for (int i = 3; ; i += 2) { |
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// We only have to try i up to the squre root of n |
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if (i > n/i) break; |
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// Now, we have i <= n/i < n. |
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// If n is divisible by i, n is not prime. |
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if (n % i == 0) return false; |
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} |
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// n has no integer factor in the range (1, n), and thus is prime. |
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return true; |
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}
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