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| 1 // Sample program demonstrating the use of the Big Integer Library. | |
| 2 | |
| 3 // Standard libraries | |
| 4 #include <string> | |
| 5 #include <iostream> | |
| 6 | |
| 7 // `BigIntegerLibrary.hh' includes all of the library headers. | |
| 8 #include "BigIntegerLibrary.hh" | |
| 9 | |
| 10 int main() { | |
| 11 /* The library throws `const char *' error messages when things go | |
| 12 * wrong. It's a good idea to catch them using a `try' block like this | |
| 13 * one. Your C++ compiler might need a command-line option to compile | |
| 14 * code that uses exceptions. */ | |
| 15 try { | |
| 16 BigInteger a; // a is 0 | |
| 17 int b = 535; | |
| 18 | |
| 19 /* Any primitive integer can be converted implicitly to a | |
| 20 * BigInteger. */ | |
| 21 a = b; | |
| 22 | |
| 23 /* The reverse conversion requires a method call (implicit | |
| 24 * conversions were previously supported but caused trouble). | |
| 25 * If a were too big for an int, the library would throw an | |
| 26 * exception. */ | |
| 27 b = a.toInt(); | |
| 28 | |
| 29 BigInteger c(a); // Copy a BigInteger. | |
| 30 | |
| 31 // The int literal is converted to a BigInteger. | |
| 32 BigInteger d(-314159265); | |
| 33 | |
| 34 /* This won't compile (at least on 32-bit machines) because the | |
| 35 * number is too big to be a primitive integer literal, and | |
| 36 * there's no such thing as a BigInteger literal. */ | |
| 37 //BigInteger e(3141592653589793238462643383279); | |
| 38 | |
| 39 // Instead you can convert the number from a string. | |
| 40 std::string s("3141592653589793238462643383279"); | |
| 41 BigInteger f = stringToBigInteger(s); | |
| 42 | |
| 43 // You can convert the other way too. | |
| 44 std::string s2 = bigIntegerToString(f); | |
| 45 | |
| 46 // f is implicitly stringified and sent to std::cout. | |
| 47 std::cout << f << std::endl; | |
| 48 | |
| 49 /* Let's do some math! The library overloads most of the | |
| 50 * mathematical operators (including assignment operators) to | |
| 51 * work on BigIntegers. There are also ``copy-less'' | |
| 52 * operations; see `BigUnsigned.hh' for details. */ | |
| 53 | |
| 54 // Arithmetic operators | |
| 55 BigInteger g(314159), h(265); | |
| 56 std::cout << (g + h) << '\n' | |
| 57 << (g - h) << '\n' | |
| 58 << (g * h) << '\n' | |
| 59 << (g / h) << '\n' | |
| 60 << (g % h) << std::endl; | |
| 61 | |
| 62 // Bitwise operators | |
| 63 BigUnsigned i(0xFF0000FF), j(0x0000FFFF); | |
| 64 // The library's << operator recognizes base flags. | |
| 65 std::cout.flags(std::ios::hex | std::ios::showbase); | |
| 66 std::cout << (i & j) << '\n' | |
| 67 << (i | j) << '\n' | |
| 68 << (i ^ j) << '\n' | |
| 69 // Shift distances are ordinary unsigned ints. | |
| 70 << (j << 21) << '\n' | |
| 71 << (j >> 10) << '\n'; | |
| 72 std::cout.flags(std::ios::dec); | |
| 73 | |
| 74 // Let's do some heavy lifting and calculate powers of 314. | |
| 75 int maxPower = 10; | |
| 76 BigUnsigned x(1), big314(314); | |
| 77 for (int power = 0; power <= maxPower; power++) { | |
| 78 std::cout << "314^" << power << " = " << x << std::endl; | |
| 79 x *= big314; // A BigInteger assignment operator | |
| 80 } | |
| 81 | |
| 82 // Some big-integer algorithms (albeit on small integers). | |
| 83 std::cout << gcd(BigUnsigned(60), 72) << '\n' | |
| 84 << modinv(BigUnsigned(7), 11) << '\n' | |
| 85 << modexp(BigUnsigned(314), 159, 2653) << std::endl; | |
| 86 | |
| 87 // Add your own code here to experiment with the library. | |
| 88 } catch(char const* err) { | |
| 89 std::cout << "The library threw an exception:\n" | |
| 90 << err << std::endl; | |
| 91 } | |
| 92 | |
| 93 return 0; | |
| 94 } | |
| 95 | |
| 96 /* | |
| 97 The original sample program produces this output: | |
| 98 | |
| 99 3141592653589793238462643383279 | |
| 100 314424 | |
| 101 313894 | |
| 102 83252135 | |
| 103 1185 | |
| 104 134 | |
| 105 0xFF | |
| 106 0xFF00FFFF | |
| 107 0xFF00FF00 | |
| 108 0x1FFFE00000 | |
| 109 0x3F | |
| 110 314^0 = 1 | |
| 111 314^1 = 314 | |
| 112 314^2 = 98596 | |
| 113 314^3 = 30959144 | |
| 114 314^4 = 9721171216 | |
| 115 314^5 = 3052447761824 | |
| 116 314^6 = 958468597212736 | |
| 117 314^7 = 300959139524799104 | |
| 118 314^8 = 94501169810786918656 | |
| 119 314^9 = 29673367320587092457984 | |
| 120 314^10 = 9317437338664347031806976 | |
| 121 12 | |
| 122 8 | |
| 123 1931 | |
| 124 | |
| 125 */ | |
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Chromium Code Reviews
Issue 773923002:
Remove unnecessary files in third_party/bigint (Closed)
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