From a321a5c412090d04dfaea4b4876c4901c42cfe44 Mon Sep 17 00:00:00 2001 From: Clifford Wolf Date: Wed, 27 Feb 2013 09:32:19 +0100 Subject: Moved stand-alone libs to libs/ directory and added libs/subcircuit --- libs/bigint/sample.cc | 125 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 125 insertions(+) create mode 100644 libs/bigint/sample.cc (limited to 'libs/bigint/sample.cc') diff --git a/libs/bigint/sample.cc b/libs/bigint/sample.cc new file mode 100644 index 00000000..62b41df3 --- /dev/null +++ b/libs/bigint/sample.cc @@ -0,0 +1,125 @@ +// Sample program demonstrating the use of the Big Integer Library. + +// Standard libraries +#include +#include + +// `BigIntegerLibrary.hh' includes all of the library headers. +#include "BigIntegerLibrary.hh" + +int main() { + /* The library throws `const char *' error messages when things go + * wrong. It's a good idea to catch them using a `try' block like this + * one. Your C++ compiler might need a command-line option to compile + * code that uses exceptions. */ + try { + BigInteger a; // a is 0 + int b = 535; + + /* Any primitive integer can be converted implicitly to a + * BigInteger. */ + a = b; + + /* The reverse conversion requires a method call (implicit + * conversions were previously supported but caused trouble). + * If a were too big for an int, the library would throw an + * exception. */ + b = a.toInt(); + + BigInteger c(a); // Copy a BigInteger. + + // The int literal is converted to a BigInteger. + BigInteger d(-314159265); + + /* This won't compile (at least on 32-bit machines) because the + * number is too big to be a primitive integer literal, and + * there's no such thing as a BigInteger literal. */ + //BigInteger e(3141592653589793238462643383279); + + // Instead you can convert the number from a string. + std::string s("3141592653589793238462643383279"); + BigInteger f = stringToBigInteger(s); + + // You can convert the other way too. + std::string s2 = bigIntegerToString(f); + + // f is implicitly stringified and sent to std::cout. + std::cout << f << std::endl; + + /* Let's do some math! The library overloads most of the + * mathematical operators (including assignment operators) to + * work on BigIntegers. There are also ``copy-less'' + * operations; see `BigUnsigned.hh' for details. */ + + // Arithmetic operators + BigInteger g(314159), h(265); + std::cout << (g + h) << '\n' + << (g - h) << '\n' + << (g * h) << '\n' + << (g / h) << '\n' + << (g % h) << std::endl; + + // Bitwise operators + BigUnsigned i(0xFF0000FF), j(0x0000FFFF); + // The library's << operator recognizes base flags. + std::cout.flags(std::ios::hex | std::ios::showbase); + std::cout << (i & j) << '\n' + << (i | j) << '\n' + << (i ^ j) << '\n' + // Shift distances are ordinary unsigned ints. + << (j << 21) << '\n' + << (j >> 10) << '\n'; + std::cout.flags(std::ios::dec); + + // Let's do some heavy lifting and calculate powers of 314. + int maxPower = 10; + BigUnsigned x(1), big314(314); + for (int power = 0; power <= maxPower; power++) { + std::cout << "314^" << power << " = " << x << std::endl; + x *= big314; // A BigInteger assignment operator + } + + // Some big-integer algorithms (albeit on small integers). + std::cout << gcd(BigUnsigned(60), 72) << '\n' + << modinv(BigUnsigned(7), 11) << '\n' + << modexp(BigUnsigned(314), 159, 2653) << std::endl; + + // Add your own code here to experiment with the library. + } catch(char const* err) { + std::cout << "The library threw an exception:\n" + << err << std::endl; + } + + return 0; +} + +/* +The original sample program produces this output: + +3141592653589793238462643383279 +314424 +313894 +83252135 +1185 +134 +0xFF +0xFF00FFFF +0xFF00FF00 +0x1FFFE00000 +0x3F +314^0 = 1 +314^1 = 314 +314^2 = 98596 +314^3 = 30959144 +314^4 = 9721171216 +314^5 = 3052447761824 +314^6 = 958468597212736 +314^7 = 300959139524799104 +314^8 = 94501169810786918656 +314^9 = 29673367320587092457984 +314^10 = 9317437338664347031806976 +12 +8 +1931 + +*/ -- cgit v1.2.3