public void set_category(String cat){
		this.category=cat;
		switch(this.category){
		case "all":
			this.category_nr=0;
			break;
		case "Light":
			this.category_nr=1;
			break;
		case "Medium":
			this.category_nr=2;
			break;
		case "Heavy":
			this.category_nr=3;
			break;            
		case "Tank Destroyer":
			this.category_nr=4;
			break;
		case "Artillery":
			this.category_nr=5;
			break;
		}
	}