题解 | Day of Week

#include<stdio.h>
#include<string.h>
using namespace std;
//首先要算出距离1年1月1日已经过了几天，再模7得到是星期几

//计算下一天的日期函数
void nextday(int& year, int& month, int& day) {
    int dayofmonth[] = { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
    //先判断是否闰年，闰年的2月是29天
    if ((year % 400 == 0) || (year % 100 != 0 && year % 4 == 0))dayofmonth[2] = 29;
    //如果天数超出
    if ((day + 1) > dayofmonth[month]) {
        //如果月份超出
        if ((month + 1) > 12) {
            year++;
            month = 1;
            day = 1;
        } else {
            month++;
            day = 1;

        }

    } else day++;
}

//开始
int main(){
    int curday,curyear,cnt=1;
    char curmonth[20]={0};
    int year=1,day=1,month=1;
    //注意字符串数组是二维数组，每个一维数组存一个字符串
     char monthTonum[13][20]={" ","January", "February", "March", "April", "May", "June", "July", "August", "September","October", "November","December"};
    char dayOfMonth[7][20]={"Monday","Tuesday","Wednesday","Thursday","Friday","Saturday","Sunday"};
    //获取输入
    scanf("%d %s %d\n",&curday,curmonth,&curyear);
    int i=1;
    //i是存月份字符串对应的数字
    while(strcmp(curmonth,monthTonum[i])!=0){
        i++;
    }
    //循环判断输入日期距离1年1月1日已经过去多少天，cnt统计天数
    while(true){
        cnt++;
        nextday(year,month,day);
        if(year==curyear&&month==i&&day==curday)break;

    }

//因为数组下标：0-周一,6-周日，故cnt-1，又有下标范围为0—6故%7
    printf("%s\n",dayOfMonth[(cnt-1)%7]);

    return 0;
}