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authorClifford Wolf <clifford@clifford.at>2013-02-27 09:32:19 +0100
committerClifford Wolf <clifford@clifford.at>2013-02-27 09:32:19 +0100
commita321a5c412090d04dfaea4b4876c4901c42cfe44 (patch)
treeb08d286e0aea76be9aab7a543df0b51e76b6ede4 /libs/bigint/sample.cc
parent4f0c2862a0d7e1ca247e0a4d54301c7f8cc92fd8 (diff)
Moved stand-alone libs to libs/ directory and added libs/subcircuit
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+// Sample program demonstrating the use of the Big Integer Library.
+
+// Standard libraries
+#include <string>
+#include <iostream>
+
+// `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
+
+*/