shubhamgarg9 / BigInt

Arbitrary-sized integer class for C++

Arbitrary-sized integer class for C++

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🚧 Work in progress 🚧

Contents

• Highlights
• Usage
• Features
• Compiling / testing
• Contributing
• License

Highlights

• No additional dependencies apart from the standard library.
• Modern C++ (compiles with C++11 / C++14 / C++17).
• No special compiling or linking required. Simply download the single header file, include it in your code, and compile however you would.

Usage

1. Download the single-include header file to a location under your include path. Then #include it in your code:

   #include "BigInt.hpp"   // the actual path may vary

2. Create objects of the BigInt class, and do what you got to do!

   BigInt num1, num2;
   num1 = 1234567890;
   num2 = "9876543210123456789098765432101234567890";
   
   std::cout << num1 * num2 * 123456 << "\n";
   // Output: 1505331490682966620443288524512589666204282352096057600

Features

Operators

All binary operators can have either an integer (upto signed long long int), a string (std::string or a string literal), or another BigInt as the second operand.

• Assignment: =

  my_big_int = 1234567890;
  my_big_int = "123456789012345678901234567890";
  my_big_int = other_big_int;

• Unary arithmetic: +, -

  my_big_int = +other_big_int;  // doesn't return the absolute value
  my_big_int = -other_big_int;

• Binary arithmetic: +, -, *, /, %

  big_int_1 = big_int_2 + 1234567890;
  big_int_1 = big_int_2 - "123456789012345678901234567890";
  big_int_1 = big_int_2 * big_int_3;
  big_int_1 = big_int_2 / 1234567890;
  big_int_1 = big_int_2 % "123456789012345678901234567890";

• Arithmetic-assignment: +=, -=, *=, /=, %=

  big_int_1 += big_int_2;
  big_int_1 -= 1234567890;
  big_int_1 *= "123456789012345678901234567890";
  big_int_1 /= big_int_2;
  big_int_1 %= 1234567890;

• Increment and decrement: ++, --

  some_big_int = ++my_big_int;   // pre-increment
  some_big_int = --my_big_int;   // pre-decrement
  
  some_big_int = my_big_int++;   // post-increment
  some_big_int = my_big_int--;   // post-decrement

• Relational: <, >, <=, >=, ==, !=

  if (big_int_1 < 1234567890
      or big_int_1 > "123456789012345678901234567890"
      or big_int_1 <= big_int_2
      or big_int_1 >= 1234567890
      or big_int_1 == "123456789012345678901234567890"
      or big_int_1 != big_int_3) {
      ...
  }

• I/O stream: <<, >>

  std::cout << big_int_1 << ", " << big_int_2 << "\n";
  output_file << big_int_1 << ", " << big_int_2 << "\n";
  
  std::cin >> big_int_1 >> big_int_2;
  input_file >> big_int_1 >> big_int_2;

Functions

• Conversion: to_string, to_int, to_long, to_long_long

  Convert a BigInt to either a string, int, long, or long long.

  Note: If the BigInt is beyond the range of the target type, an out_of_range exception is thrown.

  some_str = my_big_int.to_string();
  
  some_int = my_big_int.to_int();
  
  some_long = my_big_int.to_long();
  
  some_long_long = my_big_int.to_long_long();

• Math

  • abs

    Get the absolute value of a BigInt.

    my_big_int = abs(other_big_int);

  • big_pow10

    Get a BigInt equal to 10^x.

    my_big_int = big_pow10(5000);   // my_big_int = 10^5000

Compiling / testing

Since this project is built as a library, there are no source files. However, there are unit tests for each header file that the project is split into.

• To compile the tests, run make.
• To build and run the tests, run make test.

You will need to run make at least once before you can run make test.

Contributing

Please read the contributing guidelines for details on how to contribute to the project.

License

This project is licensed under the terms of the MIT license.