[bigint/bigint.git] / sample.cc

/*
* 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.
*
* 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;
* 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"

#include <string>
#include <iostream>

int main() {
	try {
		BigInteger a; // a is 0
		int b = 535;
		
		a = b; // From int to BigUnsigned...
		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.
		*/
		
		BigInteger c(a); // Copy them.
		
		BigInteger d(-314159265); // c is -314159265.  The `int' literal is converted to a BigInteger.
		
		// Ahem: that's too big to be an `int' literal (or even a `long' literal)!
		// Disillusion yourself now -- this won't compile.
		//BigInteger e(3141592653589793238462643383279);
		
		std::string s("3141592653589793238462643383279");
		BigInteger f = easyStringToBI(s);
		// Ah.  The string is converted to a BigInteger, and strings can be as long as you want.
		
		std::string s2 = easyBItoString(f); // You can convert the other way too.
		
		std::cout << f << std::endl; // f is stringified and send to std::cout.
		
		/*
		* 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!!
		*/
		
		BigInteger g(314159), h(265);
		// All five ``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);
		
		// Let's do some heavy lifting.
		std::cout << "Powers of 3" << std::endl;
		std::cout << "How many do you want?" << std::endl;
		int maxPower;
		std::cin >> maxPower;
		
		BigUnsigned x(1), three(3);
		for (int power = 0; power <= maxPower; power++) {
			std::cout << "3^" << power << " = " << x << std::endl;
			x *= three; // A BigInteger assignment operator
		}
		
		std::cout << "There you go.  Goodbye." << std::endl;
		
	} catch(char const* err){
		std::cout << "Sorry, the library threw an exception:\n"
			<< err << std::endl;
	}
	return 0;
}

/*
* Here is the output of a sample run of this sample program:

3141592653589793238462643383279
314424
313894
83252135
1185
134
Powers of 3
How many do you want?
2
3^0 = 1
3^1 = 3
3^2 = 9
There you go.  Goodbye.

*/
Commit	Line	Data
05780f4b MM	1	/*
	2	* Matt McCutchen's Big Integer Library
	3	* http://mysite.verizon.net/mccutchen/bigint/
	4	*/
	5
	6	/*
	7	* This sample file demonstrates the most important features of the Big Integer Library.
	8	*
	9	* To get started quickly with the library, imitate the code in `main' below.
	10	*
	11	* If you want more detail or more speed or can't find a feature here,
	12	* look in the appropriate source file. This file shows only the more ``user-friendly'' features;
	13	* the other features are messier but worth learning eventually.
	14	*
	15	* GO FORTH and play with many-digit numbers! (c.f. The TeXbook.)
	16	*/
	17
	18	#include "BigUnsigned.hh"
	19	#include "BigInteger.hh"
	20	#include "BigIntegerUtils.hh"
	21
	22	#include <string>
	23	#include <iostream>
	24
	25	int main() {
	26	try {
	27	BigInteger a; // a is 0
	28	int b = 535;
	29
	30	a = b; // From int to BigUnsigned...
	31	b = a; // ...and back, no casts required!
	32	/*
	33	* If a were too big for an int you'd get a runtime exception. The Big Integer Library
	34	* throws C-strings (that is, `const char *'s) when something goes wrong. It's a good
	35	* idea to catch them. Some C++ compilers need a special command-line option to compile
	36	* code that uses throw/catch.
	37	*/
	38
	39	BigInteger c(a); // Copy them.
	40
	41	BigInteger d(-314159265); // c is -314159265. The `int' literal is converted to a BigInteger.
	42
	43	// Ahem: that's too big to be an `int' literal (or even a `long' literal)!
	44	// Disillusion yourself now -- this won't compile.
	45	//BigInteger e(3141592653589793238462643383279);
	46
	47	std::string s("3141592653589793238462643383279");
	48	BigInteger f = easyStringToBI(s);
	49	// Ah. The string is converted to a BigInteger, and strings can be as long as you want.
	50
	51	std::string s2 = easyBItoString(f); // You can convert the other way too.
	52
	53	std::cout << f << std::endl; // f is stringified and send to std::cout.
	54
	55	/*
	56	* Let's do some math!
	57	*
	58	* The Big Integer Library provides three kinds of operators:
	59	*
	60	* (1) Overloaded ``value'' operators: +, -, *, /, %, unary -.
	61	* Big-integer code using these operators looks identical to
	62	* code using the primitive integer types. The operator takes
	63	* one or two BigInteger inputs and returns a BigInteger result,
	64	* which can then be assigned to a BigInteger variable or used
65	* in an expression.
66	*
67	* (2) Overloaded assignment operators: +=, -=, *=, /=, %=,
68	* ++, --, flipSign.
69	* Again, these are used on BigIntegers just like on ints.
70	* They take one writable BigInteger that both provides an
71	* operand and receives a result. The first five also take
72	* a second read-only operand.
73	*
74	* (3) ``Put-here'' operations: `add', `subtract', etc.
75	* Use these if and only if you are concerned about performance.
76	* They require fewer BigInteger copy-constructions and assignments
77	* than do operators in (1) or (2). Most take two read-only operands
78	* and save the result in the invoked object `*this', whose previous
79	* value is irrelevant. `divideWithRemainder' is an exception.
80	* <<< NOTE >>>: Put-here operations do not return a value: they don't need to!!
81	*/
82
83	BigInteger g(314159), h(265);
84	// All five ``value'' operators
85	std::cout << (g + h) << '\n' << (g - h) << '\n' << (g * h)
86	<< '\n' << (g / h) << '\n' << (g % h) << std::endl;
87
88	BigInteger i(5), j(10), k;
89	// These two lines do the same thing: k is set to a BigInteger containing 15.
90	k = i + j;
91	k.add(i, j);
92
93	// Let's do some heavy lifting.
94	std::cout << "Powers of 3" << std::endl;
95	std::cout << "How many do you want?" << std::endl;
96	int maxPower;
97	std::cin >> maxPower;
98
99	BigUnsigned x(1), three(3);
100	for (int power = 0; power <= maxPower; power++) {
101	std::cout << "3^" << power << " = " << x << std::endl;
102	x *= three; // A BigInteger assignment operator
103	}
104
105	std::cout << "There you go. Goodbye." << std::endl;
106
107	} catch(char const* err){
108	std::cout << "Sorry, the library threw an exception:\n"
109	<< err << std::endl;
110	}
111	return 0;
112	}
113
114	/*
115	* Here is the output of a sample run of this sample program:
116
117	3141592653589793238462643383279
118	314424
119	313894
120	83252135
121	1185
122	134
123	Powers of 3
124	How many do you want?
125	2
126	3^0 = 1
127	3^1 = 3
128	3^2 = 9
129	There you go. Goodbye.
130
131	*/