求个学Java的解个题，我输入0最小值就总是为0

这是题目，怎么写，给个思路或者给个代码

public class Max {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.print("请开始输入数据（输入0时结束循环）:");
        int num=0;
        num=sc.nextInt();
        int max=num;
        int min=num;
        while(num!=0){
            if (max<num){
                max=num;
            }else if (min>num){
                min=num;
            }
            System.out.print("请开始输入数据（输入0时结束循环）:");
            num=sc.nextInt();
        }
        System.out.println("最大值是："+max);
        System.out.println("最小值是："+min);
    }
}

int max = 0,min = 0;
Scanner cin = new Scanner(System.in);
for(;;){
int t = cin.nextInt();
if(t==0) break;
if(max == 0 && min == 0){
  max = t; min = t;
  }else{
  if(t > max) max = t;
  if(t< min) min = t;
  }
}

System.out.println("max="+max+",min="+min);

public class Test3 {
    public static void main(String[] args) {
        System.out.print("请输入一个整数（输入0结束）：");
        Scanner cin = new Scanner(System.in);
        int i = cin.nextInt();
        int max = i;
        int min = i;
        while (i!=0){
            if (max < i){
                max = i;
            } else if (min > i) {
                min = i;
            }
            System.out.print("请输入一个整数（输入0结束）：");
            Scanner cin2 = new Scanner(System.in);
             i = cin2.nextInt();
        }
            System.out.println("最大值:"+max);
            System.out.println("最小值："+min);


    }
}