example.zig

const std = @import("std");
const gmp = @import("gmp");

pub fn main() !void {
    var buf: [256]u8 = undefined;

    // 100! has 158 digits.
    var n = gmp.Int.init();
    defer n.deinit();
    n.factorial(100);
    std.log.info("100! = {s}", .{n.writeStr(10, &buf)});

    // gcd of two large integers.
    var a = gmp.Int.init();
    defer a.deinit();
    var b = gmp.Int.init();
    defer b.deinit();
    try a.setStr("12345678901234567890", 10);
    try b.setStr("98765432109876543210", 10);

    var g = gmp.Int.init();
    defer g.deinit();
    g.gcd(a, b);
    std.log.info("gcd = {s}", .{g.writeStr(10, &buf)});

    // A known Mersenne prime: 2^61 - 1.
    var p = gmp.Int.init();
    defer p.deinit();
    try p.setStr("2305843009213693951", 10);
    std.log.info("2305843009213693951 is {any}", .{p.isPrime(25)});

    // 1/3 + 1/6 = 1/2.
    var r1 = gmp.Rational.init();
    defer r1.deinit();
    var r2 = gmp.Rational.init();
    defer r2.deinit();
    r1.setU(1, 3);
    r2.setU(1, 6);
    r1.add(r2);
    r1.canonicalize();
    const rs = try r1.toString(10, std.heap.page_allocator);
    defer std.heap.page_allocator.free(rs);
    std.log.info("1/3 + 1/6 = {s}", .{rs});

    // sqrt(2) to 256 bits of precision.
    var f = gmp.Float.init2(256);
    defer f.deinit();
    f.setI(2);
    f.sqrt();
    const fs = try f.toString(10, 40, std.heap.page_allocator);
    defer std.heap.page_allocator.free(fs);
    std.log.info("sqrt(2) ~= {s}", .{fs});
}