求任意两个日期的日期间隔

struct   tagTime{ 
    int   year; 
    int   month; 
    int   day; 
}; 

void   Set(int   y,int   m,int   d,struct   tagTime   *t)/*设置日期*/ 
{ 
    t-> year=y; 
    t-> month=m; 
    t-> day=d; 
} 

int   IsLeapYear(int   year)         /*是否闰年*/ 
{ 
    return((year%4==0)&&(year%100!=0)||year%400==0); 
} 

int   GetLastDay(struct   tagTime   date)       /*得到date.month的最大天数*/ 
{ 
    int   num; 
    switch(date.month) 
    { 
    case   1: 
    case   3: 
    case   5: 
    case   7: 
    case   8: 
    case   10: 
    case   12: 
        num=31; 
        break; 
    case   2: 
        num=   28+IsLeapYear(date.year); 
        break; 
    default: 
        num=   30; 
    } 
    return   num; 
} 

int   IsDateValid(struct   tagTime   date)         /*日期是否合法*/ 
{ 
    if(date.year <0||date.month <1||date.month> 12) 
        return   0; 
    if(date.day <1||date.day> GetLastDay(date))return   0; 
    return   1; 
} 

void   AddDay(struct   tagTime   *date)       /*date+1*/ 
{ 
    date-> day++; 
    if(date-> day> GetLastDay(*date)) 
    { 
        date-> day=1;date-> month++; 
        if(date-> month> 12){ 
            date-> month=1; 
            date-> year++; 
        } 
    } 
} 

int   Compare(struct   tagTime   t1,struct   tagTime   t2)   /*t1比t2小返回值为1，否则为0*/ 
{ 
    if(t1.year <t2.year)return   1; 
    if(t1.year <=t2.year&&t1.month <t2.month)   return   1; 
    if(t1.year <=t2.year&&t1.month <=t2.month&&t1.day <t2.day)   return   1; 
    return   0; 
} 

long   CountDate(struct   tagTime   t1,struct   tagTime   t2) 
{ 
    long   delta=0;struct   tagTime   t3; 
    if(!Compare(t1,t2))/*若t1> t2,交换t1,t2*/ 
    { 
        t3=t2;t2=t1;t1=t3; 
    } 
    while(Compare(t1,t2))/*本方法是笨方法，但很直观，t1比t2少时，t1日期加1*/ 
    { 
        AddDay(&t1); 
        delta++; 
    } 
    return   delta; 
} 

void   main() 
{ 
    struct   tagTime   t1,t2,t3; 
    int   y,m,d;clrscr(); 
    while(1) 
    {     
        puts( "\nInput   t1\t "); 
        scanf( "%d,%d,%d ",&y,&m,&d); 
        Set(y,m,d,&t1); 
        if(!IsDateValid(t1)) 
        { 
            puts( "T1   is   invalid "); 
            exit(1); 
        } 
        puts( "\nInput   t2\t "); 
        scanf( "%d,%d,%d ",&y,&m,&d); 
        Set(y,m,d,&t2); 
        if(!IsDateValid(t2)) 
        { 
            puts( "T2   is   invalid "); 
            exit(1); 
        } 
        printf( "\n[%ld] ",CountDate(t1,t2)); 
    } 
} 

原文地址: http://topic.csdn.net/t/20010611/13/154695.html