snikolaj / bigint

A lightweight big integer library for c++

• Description
• Operators
  • Addition
  • Subtraction
  • Multiplication
  • Allocation
  • Comparison
  • Access
  • Streaming operators
• Methods
  • clear
  • abs
  • pow
  • digits
  • trailing_zeros
• Functions
  • abs
  • to_string
  • factorial

Description

Bigint class provides math operations for arbitrarily large numbers. You know the limit is reached when your computer freezes.

Operators

Addition

Dodecahedron::Bigint a,b,c;
c = a + b;
c += a;
c = a + 6;
c += 6;

Subtraction

Dodecahedron::Bigint a,b,c;
c = a - b;
c -= a;

Multiplication

Dodecahedron::Bigint a,b,c;
c = a * b;
c *= a;
c = a * 6;
c *= 6;

Allocation

Dodecahedron::Bigint a = 12345;
Dodecahedron::Bigint b;
b = 159753;

Comparison

Dodecahedron::Bigint a = 159753;
Dodecahedron::Bigint b = 1634687496;

if(a == b) cout << "A is the same as B";
if(a < b) cout << "A is less than B";
if(a > b) cout << "A is larger than B";
if(a >= b) cout << "A is larger than B or equal to it";
if(a <= b) cout << "A is smaller than B or equal to it";

Access

Dodecahedron::Bigint a = 159753;
a.pow(15); //a^15, 1126510743106482...
cout << a[3]; // 6 is the 4th digit

Stream operators

Dodecahedron::Bigint a,b;
cin >> a >> b;
cout << a*b;

Methods

clear()

Clears the Dodecahedron::Bigint, essentially making it equal to 0.

Dodecahedron::Bigint a = 4558;
cout << a.pow(486);;  // ~1.46 * 10^1778
a.clear();
cout << a; //0

abs()

Absolute value.

Dodecahedron::Bigint a = -4558;
cout << a.abs() // 4558

pow(int)

Raises to the power of N.

Dodecahedron::Bigint a = 4558;
cout << a.pow(486); // ~1.46 * 10^1778

digits()

Returns the number of digits.

Dodecahedron::Bigint a = 4558;
cout << a.pow(486).digits(); // 4558^486 = 1779 digit number

trailing_zeros()

Returns the number of trailing zeros.

Dodecahedron::Bigint a = 4558;
a.pow(486);
cout << a.trailing_zeros(); //972

Functions

abs(Bigint)

Same as abs, but returns a new instance;

Dodecahedron::Bigint a = -455897864531248;
cout << abs(a) // 455897864531248

to_string(Bigint)

Converts the big integer to a string.

string str;
Dodecahedron::Bigint a = 455897864531248;
str = to_string(a);

factorial(int)

Returns a factorial of an integer, aka n!

cout << Dodecahedron::factorial(20000); //70`000+ digit number