https://github.com/adam-mcdaniel/bigint
A library for arbitrarily large integers📐, written in C
https://github.com/adam-mcdaniel/bigint
biginteger c header-only library math
Last synced: 10 months ago
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A library for arbitrarily large integers📐, written in C
- Host: GitHub
- URL: https://github.com/adam-mcdaniel/bigint
- Owner: adam-mcdaniel
- License: mit
- Created: 2024-04-09T23:42:54.000Z (almost 2 years ago)
- Default Branch: main
- Last Pushed: 2024-04-10T03:15:06.000Z (almost 2 years ago)
- Last Synced: 2025-03-24T22:51:23.192Z (10 months ago)
- Topics: biginteger, c, header-only, library, math
- Language: C
- Homepage: https://adam-mcdaniel.net
- Size: 1.18 MB
- Stars: 6
- Watchers: 2
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# bigint
This repository implements a big integer library in C. The library supports many operations, such as basic arithmetic, comparison, fast modular exponentiation, prime number detection, square roots, and more.
## Usage
To use the library, first include it in your C file.
```c
#include "bigint.h"
```
To create a new big integer, use the `bigint` struct. You can initialize a big integer from a string, an integer, or another big integer.
```c
int main() {
// Initialize a big integer from a string
bigint a = bigint_from_string("123456789012345678901234567890");
// Initialize a big integer from an integer
bigint b = bigint_from_int(1234567890);
// Initialize a big integer from another big integer
bigint c = bigint_copy(a);
bigint_delete(a);
bigint_delete(b);
bigint_delete(c);
return 0;
}
```
To perform arithmetic operations on big integers, use the provided functions.
```c
int main() {
// Initialize big integers
bigint a = bigint_from_string("123456789012345678901234567890");
bigint b = bigint_from_string("987654321098765432109876543210");
// Perform arithmetic operations
bigint c = bigint_add(a, b);
bigint d = bigint_sub(a, b);
bigint e = bigint_mul(a, b);
bigint f = bigint_div(a, b);
bigint g = bigint_mod(a, b);
bigint_delete(a);
bigint_delete(b);
bigint_delete(c);
bigint_delete(d);
bigint_delete(e);
bigint_delete(f);
bigint_delete(g);
return 0;
}
```
To compare big integers:
```c
int main() {
// Initialize big integers
bigint a = bigint_from_string("123456789012345678901234567890");
bigint b = bigint_from_string("987654321098765432109876543210");
// Compare big integers
if (bigint_eq(a, b)) {
printf("a == b\n");
} else if (bigint_lt(a, b)) {
printf("a < b\n");
} else if (bigint_gt(a, b)) {
printf("a > b\n");
}
bigint_delete(a);
bigint_delete(b);
return 0;
}
```
To perform fast modular exponentiation:
```c
int main() {
// Initialize big integers
bigint a = bigint_from_string("2");
bigint b = bigint_from_string("1234");
bigint m = bigint_from_string("10007");
// Perform fast modular exponentiation
bigint c = bigint_fast_pow(a, b, m);
bigint_delete(a);
bigint_delete(b);
bigint_delete(c);
bigint_delete(m);
return 0;
}
```
To check if a big integer is prime:
```c
int main() {
// Initialize a big integer
bigint a = bigint_from_string("123456789012345678901234567890");
// Check if the big integer is prime
if (bigint_is_prime(a)) {
printf("a is prime\n");
} else {
printf("a is not prime\n");
}
bigint_delete(a);
return 0;
}
```
To calculate the square root of a big integer:
```c
int main() {
// Initialize a big integer
bigint a = bigint_from_string("123412341");
// Calculate the square root
bigint b = bigint_sqrt(a);
bigint_delete(a);
bigint_delete(b);
return 0;
}
```
## Building
To build your program with the big integer library, simply add it to your include path and link against the C standard library.
```bash
gcc -I path/to/bigint main.c -o main
```
### CMake
To build with CMake, you can use a `CMakeLists.txt` file like the following:
```cmake
cmake_minimum_required(VERSION 3.0)
# Create a new project
project(HelloWorld)
# Add an executable
add_executable(HelloWorld main.c)
include_directories(path/to/bigint)
```
Alternatively, you can use `FetchContent` to download the big integer repository and include it in your project.
```cmake
# Import the library from the git repo
include(FetchContent)
FetchContent_Declare(
bigint
GIT_REPOSITORY https://github.com/adam-mcdaniel/bigint
GIT_TAG main
)
FetchContent_MakeAvailable(bigint)
# Include the header only library
include_directories(${bigint_SOURCE_DIR})
```
## License
This project is licensed under the MIT License - see the [LICENSE](LICENSE) file for details.