s21_decimal

A C library for high-precision decimal arithmetic, supporting numbers up to ±79228162514264337593543950335 (equivalent to three 0xFFFFFFFFs).

Library is developed as a practice project at School 21 (formerly 42.fr).

Features

• Custom decimal data type (s21_decimal) for precise arithmetic
• Arithmetic operations: addition, subtraction, multiplication, division
• Comparison functions
• Type conversion utilities
• Rounding and truncation operations

Installation

To use the s21_decimal library in your project:

1. Clone the repo and build the library:

git clone https://github.com/makesnosense/s21_decimal.git
cd s21_decimal/src
make

2. Include the header file in your C project:

#include "s21_decimal.h"

3. Link against the built library when compiling your project. Replace /path/to/library/directory with the actual path where s21_decimal.a is located:

gcc your_program.c -L/path/to/library/directory -ls21_decimal -o your_program

Testing

git clone https://github.com/makesnosense/s21_decimal.git
cd s21_decimal/src

To run test suites (Check library required):

make test

To generate a code coverage report (requires GCOVR library):

make gcov_report

Test Generator

The project includes a test generator (s21_decimal/tests_generator/decimal.ipynb) implemented as a Jupyter Notebook. To use it:

• Open decimal.ipynb in Jupyter Notebook or JupyterLab
• Run the cells to generate test cases
• Copy the generated test cases from tests_body.txt and addition.txt into your test files

API Reference

Arithmetic

int s21_add(s21_decimal value_1, s21_decimal value_2, s21_decimal* result)
int s21_sub(s21_decimal value_1, s21_decimal value_2, s21_decimal* result)
int s21_mul(s21_decimal value_1, s21_decimal value_2, s21_decimal* result)
int s21_div(s21_decimal value_1, s21_decimal value_2, s21_decimal* result)

Comparison

int s21_is_less(s21_decimal decimal_1, s21_decimal decimal_2)
int s21_is_less_or_equal(s21_decimal decimal_1, s21_decimal decimal_2)
int s21_is_greater(s21_decimal decimal_1, s21_decimal decimal_2)
int s21_is_greater_or_equal(s21_decimal decimal_1, s21_decimal decimal_2)
int s21_is_equal(s21_decimal decimal_1, s21_decimal decimal_2)
int s21_is_not_equal(s21_decimal decimal_1, s21_decimal decimal_2)

Conversion

int s21_from_int_to_decimal(int src, s21_decimal* dst)
int s21_from_float_to_decimal(float src, s21_decimal* dst)
int s21_from_decimal_to_int(s21_decimal src, int* dst)
int s21_from_decimal_to_float(s21_decimal src, float* dst)

Other operations

int s21_floor(s21_decimal value, s21_decimal* result)
int s21_round(s21_decimal value, s21_decimal* result)
int s21_truncate(s21_decimal value, s21_decimal* result)
int s21_negate(s21_decimal value, s21_decimal* result)