c++ strchr函数_strchr函数返回_模拟实现strchr函数(52)

struct date{

intyear,month,day;

};

inline int leap(int year){

return(year%4==0&&year%100!=0)||year%400==0;

}

inline int legal(date a){

if(a.month<0||a.month>12)

return 0;

if(a.month==2)

returna.day>0&&a.day<=28leap(a.year);

returna.day>0&&a.day<=days[a.month-1];

}

inline int datecmp(date a,date b){

if(a.year!=b.year)

return a.year-b.year;

if(a.month!=b.month)

return a.month-b.month;

return a.day-b.day;

}

int weekday(date a){

inttm=a.month>=3?(a.month-2):(a.month10);

intty=a.month>=3?a.year:(a.year-1);

return(tyty/4-ty/100ty/400(int)(2.6*tm-0.2)a.day)%7;

}

int date2int(date a){

intret=a.year*365(a.year-1)/4-(a.year-1)/100(a.year-1)/400,i;

days[1]=leap(a.year);

for(i=0;i<a.month-1;ret=days[i]);

days[1]=28;

returnreta.day;

}

date int2date(int a){

dateret;

ret.year=a/146097*400;

for(a%=146097;a>=365leap(ret.year);a-=365leap(ret.year),ret.year);

days[1]=leap(ret.year);

for(ret.month=1;a>=days[ret.month-1];a-=days[ret.month-1],ret.month);

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