function plusMinus(arr: number[]): void {
    const d: number = arr.length;
    let p: number = 0;
    let z: number = 0;
    let n: number = 0;
    
    arr.forEach((num): number => num > 0 ?  p++ : num < 0 ? n++ : z++);
   
    [p, n, z].forEach((c): void => console.log((c/d).toFixed(6)));
}