exercism/zig/triangle/triangle.zig

pub const TriangleError = error{Invalid};

pub const Triangle = struct {
    a: f64,
    b: f64,
    c: f64,

    fn isValid(a: f64, b: f64, c: f64) bool {
        return (a > 0 and b > 0 and c > 0) and (a + b >= c and b + c >= a and a + c >= b);
    }

    pub fn init(a: f64, b: f64, c: f64) TriangleError!Triangle {
        if (!isValid(a, b, c)) {
            return error.Invalid;
        }

        return Triangle{ .a = a, .b = b, .c = c };
    }

    pub fn isEquilateral(self: Triangle) bool {
        return self.a == self.b and self.b == self.c;
    }

    pub fn isIsosceles(self: Triangle) bool {
        return self.a == self.b or self.a == self.c or self.b == self.c;
    }

    pub fn isScalene(self: Triangle) bool {
        return self.a != self.b and self.a != self.c and self.b != self.c;
    }
};