Integers of Arbitrary Length

Example

#include <LEDA/numbers/integer.h>

leda::integer factorial(int n)
{
  leda::integer fac=1;
  int i;
  for (i=2; i<=n; i++) fac=fac*i;
  return fac;
}	

int main()
{
  int i;
  for (i=0;i<100;i++) {
    std::cout << "factorial(" << i << ")=" 
              << factorial(i) << std::endl;
  }
  
  return 0;
} 

Strengths

• no overflow/underflow like built-in type int
• always yields exact result
• can be used like int and together with built-in number types
• many arithmetic operations, like square root, greatest common divisor,… , predefined
• efficient implementation
• space efficient (no intermediate results are stored)

Disadvantages

• about 30-100 times slower than double

Tips

• Use integers if you need exact arithmetic
• Use integers if you can not afford overflow/underflow
• Use integers if you do not know how big your (interger) numbers will become

See also:

Algebraic Real Numbers

Rational Numbers

Big Floatingpoint Numbers

Floating Point Filter

Interval Arithmetic

Vectors and Matrices with Integer Entries

Vectors and Matrices with Double Entries

Rational Vectors

Functions of numerical analysis

Geometric Algorithms

Manual Entries:

Manual Page Integers of Arbitrary Length