// Dienstklasse zum Speichern von Anwendungsdaten
 import { Injectable } from '@angular/core';

 @Injectable()
 export class StackService {
   public datas: any[] = [];
   add(obj: any): void { this.datas.push(obj); };
   avg(fld: string): number {
     if (this.datas.length > 0) {
       return this.rnd(this.datas.reduce((s, o) => s + parseFloat(o[fld]), 0)/this.datas.length);
     };
     return 0;
   };
   rnd(val: number, digits: number = 2) {
     let pre = Math.pow(10, digits);
     return Math.round(val*pre)/pre;
   };
 }