| 1 | /* |
| 2 | * Matt McCutchen's Big Integer Library |
| 3 | * |
| 4 | * Sample program demonstrating the most important features of the Big |
| 5 | * Integer Library |
| 6 | */ |
| 7 | |
| 8 | // Standard libraries |
| 9 | #include <string> |
| 10 | #include <iostream> |
| 11 | |
| 12 | // For the BigInteger class itself. |
| 13 | #include "BigInteger.hh" |
| 14 | |
| 15 | // For the 4 routines `easy BI/BU <=> string' and `iostream' integration. |
| 16 | #include "BigIntegerUtils.hh" |
| 17 | |
| 18 | int main() { |
| 19 | try { |
| 20 | BigInteger a; // a is 0 |
| 21 | int b = 535; |
| 22 | |
| 23 | a = b; // From int to BigInteger... |
| 24 | b = a; // ...and back, no casts required! |
| 25 | /* |
| 26 | * If a were too big for an int you'd get a runtime exception. |
| 27 | * The Big Integer Library throws C-strings (that is, |
| 28 | * `const char *'s) when something goes wrong. It's a good idea |
| 29 | * to catch them; the `try/catch' construct wrapping all this |
| 30 | * code is an example of how to do this. Some C++ compilers need |
| 31 | * a special command-line option to compile code that uses |
| 32 | * exceptions. |
| 33 | */ |
| 34 | |
| 35 | BigInteger c(a); // Copy a BigInteger. |
| 36 | |
| 37 | // d is -314159265. The `int' literal is converted to a |
| 38 | // BigInteger. |
| 39 | BigInteger d(-314159265); |
| 40 | |
| 41 | // This won't compile because the number is too big to be an |
| 42 | // integer literal. |
| 43 | //BigInteger e(3141592653589793238462643383279); |
| 44 | |
| 45 | // Instead you can convert the number from a string. |
| 46 | std::string s("3141592653589793238462643383279"); |
| 47 | BigInteger f = easyStringToBI(s); |
| 48 | |
| 49 | // You can convert the other way too. |
| 50 | std::string s2 = easyBItoString(f); |
| 51 | |
| 52 | // f is stringified and send to std::cout. |
| 53 | std::cout << f << std::endl; |
| 54 | |
| 55 | /* |
| 56 | * Let's do some math! |
| 57 | * |
| 58 | * The Big Integer Library provides lots of overloaded operators |
| 59 | * and corresponding assignment operators. So you can do `a + b' |
| 60 | * with BigIntegers just as with normal integers. The named |
| 61 | * methods `add', `divideWithRemainder', etc. are more advanced |
| 62 | * ``put-here operations''; see `BigUnsigned.hh' for details. |
| 63 | */ |
| 64 | BigInteger g(314159), h(265); |
| 65 | // All five ``return-by-value'' arithmetic operators. |
| 66 | std::cout << (g + h) << '\n' << (g - h) << '\n' << (g * h) |
| 67 | << '\n' << (g / h) << '\n' << (g % h) << std::endl; |
| 68 | |
| 69 | BigUnsigned i(0xFF0000FF), j(0x0000FFFF); |
| 70 | // All five ``return-by-value'' bitwise operators. |
| 71 | std::cout.flags(std::ios::hex | std::ios::showbase); |
| 72 | std::cout << (i & j) << '\n' << (i | j) << '\n' << (i ^ j) << '\n' |
| 73 | << (j << 21) << '\n' << (j >> 10) << '\n'; |
| 74 | std::cout.flags(std::ios::dec); |
| 75 | |
| 76 | // Let's do some heavy lifting and calculate powers of 314. |
| 77 | int maxPower = 10; |
| 78 | BigUnsigned x(1), big314(314); |
| 79 | for (int power = 0; power <= maxPower; power++) { |
| 80 | std::cout << "314^" << power << " = " << x << std::endl; |
| 81 | x *= big314; // A BigInteger assignment operator |
| 82 | } |
| 83 | |
| 84 | /* |
| 85 | * If you want to experiment with the library, |
| 86 | * you can add your own test code here. |
| 87 | */ |
| 88 | // std::cout << "Beginning of custom test code:" << std::endl; |
| 89 | |
| 90 | } catch(char const* err) { |
| 91 | std::cout << "The library threw an exception:\n" |
| 92 | << err << std::endl; |
| 93 | } |
| 94 | |
| 95 | return 0; |
| 96 | } |
| 97 | |
| 98 | /* |
| 99 | Running the sample program produces this output: |
| 100 | |
| 101 | 3141592653589793238462643383279 |
| 102 | 314424 |
| 103 | 313894 |
| 104 | 83252135 |
| 105 | 1185 |
| 106 | 134 |
| 107 | 0xFF |
| 108 | 0xFF00FFFF |
| 109 | 0xFF00FF00 |
| 110 | 0x1FFFE00000 |
| 111 | 0x3F |
| 112 | 314^0 = 1 |
| 113 | 314^1 = 314 |
| 114 | 314^2 = 98596 |
| 115 | 314^3 = 30959144 |
| 116 | 314^4 = 9721171216 |
| 117 | 314^5 = 3052447761824 |
| 118 | 314^6 = 958468597212736 |
| 119 | 314^7 = 300959139524799104 |
| 120 | 314^8 = 94501169810786918656 |
| 121 | 314^9 = 29673367320587092457984 |
| 122 | 314^10 = 9317437338664347031806976 |
| 123 | |
| 124 | */ |