switch.md

# switch

我们希望编写一个函数，统计一个 `List<Integer>` 列表中的数值分布，其中 1 
是 small，2 是 middle, 3 是 big，3以上都是 huge 。列表中的数值全部都在
1 到 5之间，下列哪个程序会在对象的 small, middle, big, huge 四个字段
保存正确的统计结果？

## 答案

```java
public class Counter{
    int small = 0;
    int middle = 0;
    int big = 0;
    int huge = 0;
    //... getter methods

    public void read(List<Integer> numbers){
        for(var value: numbers){
            switch(value){
            case 1:
                small += 1;
                break;
            case 2:
                middle += 1;
                break;
            case 3:
                big += 1;
                break;
            default:
                huge +=1;
            }
        }
    }
}
```

## 选项

### A

```java
public class Counter{
    int small = 0;
    int middle = 0;
    int big = 0;
    int huge = 0;
    //... getter methods

    public void read(List<Integer> numbers){
        for(var value: numbers){
            switch(value){
            case 1:
                small += 1;
            case 2:
                middle += 1;
            case 3:
                big += 1;
            default:
                huge +=1;
            }
        }
    }
}
```

### B

```java
public class Counter{
    int small = 0;
    int middle = 0;
    int big = 0;
    int huge = 0;
    //... getter methods

    public void read(List<Integer> numbers){
        for(var value: numbers){
            switch(value){
            case 1:
                small += 1;
                return small;
            case 2:
                middle += 1;
                return middle;
            case 3:
                big += 1;
                return big;
            default:
                huge +=1;
                return huge;
            }
        }
    }
}
```

### C

```java
public class Counter{
    int small = 0;
    int middle = 0;
    int big = 0;
    int huge = 0;
    //... getter methods

    public void read(List<Integer> numbers){
        for(var value: numbers){
            switch(value){
            case 1:
                small += 1;
                return value;
            case 2:
                middle += 1;
                return value;
            case 3:
                big += 1;
                return value;
            default:
                huge +=1;
                return value;
            }
        }
    }
}
```

### D

```java
public class Counter{
    int small = 0;
    int middle = 0;
    int big = 0;
    int huge = 0;
    //... getter methods

    public void read(List<Integer> numbers){
        for(var value: numbers){
            switch(value){
            case 1:
                small += 1;
                break;
            case 2:
                middle += 1;
                break;
            case 3:
                big += 1;
                break;
            default:
                huge +=1;
            }
        }
    }
}
```