# 星期一

整个20世纪（1901年1月1日至2000年12月31日之间），一共有多少个星期一？(不要告诉我你不知道今天是星期几)

以下程序实现了这一功能，请你补全以下空白处内容：

```c
#include <stdio.h>
int main()
{
    int year, day, dayrun = 0, dayping = 0, sumday = 0;
    int count = 0;

    for (year = 1901; year <= 2000; year++)
    {
        if ((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0))
        {
            dayrun += 366;
        }
        else
        {
            dayping += 365;
        }
    }

    sumday = dayrun + dayping;

    __________________________;
    printf("%d", count);
    return 0;
}
```


## 答案

```c
for (day = 2; day <= sumday - 7; day += 7)
{
    count++;
}
```

## 选项

### A

```c
for (day = 2; day <= sumday; day += 7)
{
    count++;
}
```

### B

```c
for (day = 2; day < sumday; day += 7)
{
    count++;
}
```

### C

```c
for (day = 2; day <= sumday - 7; day++)
{
    count++;
}
```