/*
* Matt McCutchen's Big Integer Library
-* http://mysite.verizon.net/mccutchen/bigint/
*/
/*
-* This sample file demonstrates the most important features of the Big Integer Library.
+* This sample program demonstrates the most important features of the Big Integer Library.
+* To get started quickly, read the code and explanations below. Then try the program out.
*
-* To get started quickly with the library, imitate the code in `main' below.
-*
-* If you want more detail or more speed or can't find a feature here,
-* look in the appropriate source file. This file shows only the more ``user-friendly'' features;
+* If you want more detail or more speed or can't find a feature here, look in the
+* appropriate source file. This file shows only the more ``user-friendly'' features;
* the other features are messier but worth learning eventually.
*
* GO FORTH and play with many-digit numbers! (c.f. The TeXbook.)
*/
-#include "BigUnsigned.hh"
-#include "BigInteger.hh"
-#include "BigIntegerUtils.hh"
-
+// Standard libraries
#include <string>
#include <iostream>
+// For the BigInteger class itself.
+#include "BigInteger.hh"
+
+// For the 4 routines `easy BI/BU <=> string' and `iostream' integration.
+#include "BigIntegerUtils.hh"
+
int main() {
try {
+ std::cout << "=====\nBig Integer Library Demonstration" << std::endl;
+
BigInteger a; // a is 0
int b = 535;
- a = b; // From int to BigUnsigned...
+ a = b; // From int to BigInteger...
b = a; // ...and back, no casts required!
/*
* If a were too big for an int you'd get a runtime exception. The Big Integer Library
* throws C-strings (that is, `const char *'s) when something goes wrong. It's a good
- * idea to catch them. Some C++ compilers need a special command-line option to compile
- * code that uses throw/catch.
+ * idea to catch them; the `try/catch' construct wrapping all this code is an example
+ * of how to do this. Some C++ compilers need a special command-line option to compile
+ * code that uses exceptions.
*/
- BigInteger c(a); // Copy them.
+ BigInteger c(a); // Copy a BigInteger.
BigInteger d(-314159265); // c is -314159265. The `int' literal is converted to a BigInteger.
/*
* Let's do some math!
*
- * The Big Integer Library provides three kinds of operators:
- *
- * (1) Overloaded ``value'' operators: +, -, *, /, %, unary -.
- * Big-integer code using these operators looks identical to
- * code using the primitive integer types. The operator takes
- * one or two BigInteger inputs and returns a BigInteger result,
- * which can then be assigned to a BigInteger variable or used
- * in an expression.
- *
- * (2) Overloaded assignment operators: +=, -=, *=, /=, %=,
- * ++, --, flipSign.
- * Again, these are used on BigIntegers just like on ints.
- * They take one writable BigInteger that both provides an
- * operand and receives a result. The first five also take
- * a second read-only operand.
- *
- * (3) ``Put-here'' operations: `add', `subtract', etc.
- * Use these if and only if you are concerned about performance.
- * They require fewer BigInteger copy-constructions and assignments
- * than do operators in (1) or (2). Most take two read-only operands
- * and save the result in the invoked object `*this', whose previous
- * value is irrelevant. `divideWithRemainder' is an exception.
- * <<< NOTE >>>: Put-here operations do not return a value: they don't need to!!
+ * The Big Integer Library provides lots of overloaded operators
+ * and corresponding assignment operators. So you can do `a + b'
+ * with big integers just as with normal integers. The named
+ * methods `add', `divideWithRemainder', etc. are more advanced
+ * ``put-here operations''; see `BigUnsigned.hh' for details.
*/
-
BigInteger g(314159), h(265);
- // All five ``value'' operators
+ // All five ``return-by-value'' operators.
std::cout << (g + h) << '\n' << (g - h) << '\n' << (g * h)
<< '\n' << (g / h) << '\n' << (g % h) << std::endl;
- BigInteger i(5), j(10), k;
- // These two lines do the same thing: k is set to a BigInteger containing 15.
- k = i + j;
- k.add(i, j);
+ std::cout << "=====\nTest code" << std::endl;
+
+ /*
+ * If you want to experiment with the library,
+ * put your own test code here.
+ */
+
+ /*
+ * (End of test code)
+ */
// Let's do some heavy lifting.
- std::cout << "Powers of 3" << std::endl;
+ std::cout << "=====\nPowers of 3" << std::endl;
std::cout << "How many do you want?" << std::endl;
int maxPower;
std::cin >> maxPower;
x *= three; // A BigInteger assignment operator
}
- std::cout << "There you go. Goodbye." << std::endl;
+ std::cout << "There you go. Goodbye.\n=====" << std::endl;
- } catch(char const* err){
- std::cout << "Sorry, the library threw an exception:\n"
+ } catch(char const* err) {
+ std::cout << "=====\nSorry, the library threw an exception:\n"
<< err << std::endl;
}
+
return 0;
}
Matt McCutchen's Web Site / bigint / bigint.git / blobdiff