《C程序设计语言》
#include <stdio.h>
/*练习二维数组,判断给出的天数是某年中的几月几日;
或判断给出的日期是某年中的第几天
*/
int day_year(int year, int month, int day);
void day_month(int yearday, int year, int*, int*);
char daylab[2][13] = {{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}, {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}};
int main()
{
int day;
int *pday = NULL, *pmonth = NULL;
int d, m, y;
printf("请依次输入年月日:\n");
scanf("%d%d%d", &y, &m, &d);
day = day_year(y, m, d);
printf("%d年的%d月%d日是这一年的第%d天\n", y, m, d, day);
day_month(day, y, pday, pmonth);
return 0;
}
int day_year(int year, int month, int day)
{
int leap, yearday = 0;
int i;
leap = (year % 100 == 0 && year % 4 == 0) || year % 400 == 0; //还可以利用逻辑语句这样进行赋值
if(year <= 0 || month < 0 || month > 12 || day < 0 || day > daylab[leap][month])
return -1;
for(i = 1; i < month; i++){
yearday += daylab[leap][i];
}
yearday += day;
return yearday;
}
void day_month(int yearday, int year, int *day, int *month)
{
int leap = 0, i;
leap = (year % 4 == 0 && year % 100 == 0) || year % 400 == 0;
if(leap == 0){ //个人总结:要对输入的变量进行判断,这是我经常忽略的,或者说是想不到的事情。
if(yearday > 365)
return -1;
}
else if(leap == 1){
if(yearday > 366)
return -1;
}
if(year <= 0)
return -1;
for(i = 1; yearday >= daylab[leap][i]; i++){
yearday -= daylab[leap][i];
//printf("%d ", yearday);
}
day = &yearday; //【这个地方,一开始我写的*day = yearday, 一直编译有错误,后来我总结出来的错误原因:函数传进来的指针是要带回去地址的,所以不能对指针变量赋值,要对指针赋值地址。】
month = &i;
printf("%d %d\n", *month, *day);
}