C/C++编程笔记：C语言编写大学实验课项目——万年历！全解

#include <time.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#define PAUSE() system("pause")
#define CLEAR() system("cls")
#define rep(i,a,b) for(int i=a;i<=b;i++)
char wday_[7][7]={"Sun. |","Mon. |","Tues.|","Wed. |","Thur.|","Fri. |","Sat.  "};
char div_line[]="============================================================";
char _16bas[]="0123456789abcdef";
void color_change(){
    /*change the color of cmd in random*/
    static char cmd_[] = "color f0";
    cmd_[7]=_16bas[rand()%7];
    system(cmd_);
}
void _statement(){
    color_change();
    printf(
        "n"
        "============================================================n"
        "Welcome to use Permanent Calendar by Qing_!n"
        "Here, you can see the monthly calendar now.n"
        "Here, you can query the calendar for anyday.n"
        "Come on, study-human! Now, enjoy your time!n"
        "Notice: I will use Chinese English to talk with you.n"
        "============================================================n"
        "n"
    );
    PAUSE(); CLEAR();
}
void put_space(int x){ while(x) x--,putchar(' '); }
void i_am_doing(){
    /*To tell user that I'm calucating.*/
    static int cc=0,p=0;
    cc=(cc+1)%25; if(cc>0) return;
    p=(p+1)%27;

    CLEAR();
    printf("n%snNow calucatingn",div_line);
    rep(i,1,p) putchar('.'); putchar('n');
    printf("%sn",div_line);
}

/*----------------------------------------------------------------------------*/

struct DATE{ int year,mon,day,wday; };
int c_day[]={0,31,0,31,30,31,30,31,31,30,31,30,31};
int bas_Y=1900;

void Fix_Mode(){
    /* May be your bas_Y is not 1900. */
    color_change(); CLEAR();
    printf(
        "%snHere is Fix-Mode.n"
        "This is an important step.nPlease input a correct year.n"
        "Before use, input the year today like this:n2020n"
        "To fix the base year of different system.n%sn",div_line,div_line
    );
    printf("The year today is:"),scanf("%d",&bas_Y);
    time_t now; time(&now);
    struct tm *t=localtime(&now);
    bas_Y-=t->tm_year;
    printf("Done. Press any key to see the change.n");
    PAUSE();
}
void input_date(struct DATE *A,int y,int m,int d,int w){
    /* Maybe i havenot use this */
    A->day=d; A->mon=m; A->year=y; A->wday=w;
}
void get_date(struct DATE *A,struct tm *t){
    /* Notice: tm_year is a delta with 1900, tm_mon is [0,11] */
    A->day=t->tm_mday; A->mon=t->tm_mon+1; 
    A->wday=t->tm_wday; A->year=t->tm_year+bas_Y;
}
int is_leap_year(int year){
    return year%100==0 ? year%400==0 : year%4==0;
}
int legal_judge(struct DATE *Q){
    if(Q->day<=0||Q->mon<=0) return 0;
    if(Q->mon>12||Q->day>31) return 0;
    if(Q->mon==2) return is_leap_year(Q->year)?Q->day<=29:Q->day<=28;
    return Q->day<=c_day[Q->mon];
}
int get_wday(int wday,int delta){
    wday+=delta;
    return wday<0?wday-wday/7*7+7:wday%7;
}
int get_day(struct DATE *Q){
    if(Q->mon==2) return is_leap_year(Q->year)?29:28;
    return c_day[Q->mon];
}
void _display(struct DATE *Q){
    /* To display the date. */
    /* The head */
    if(is_leap_year(Q->year)) printf("Do you know? %d is a leap year ~n",Q->year);
    else printf("Wuhu, i want to fly ~n");
    printf("Here: %d-%dn",Q->year,Q->mon);
    rep(i,0,6) printf("%s",wday_[i]); putchar('n');
    /* what day is it? */
    int _wday=get_wday(Q->wday,-Q->day+1),mDAY=get_day(Q);
    rep(i,0,_wday-1) put_space(2),putchar('/'),put_space(2),putchar('|');
    rep(i,1,mDAY){
        printf(i!=Q->day?" %2d  ":"[%2d] ",i);
        putchar(_wday==6?'n':'|');
        _wday=(_wday+1)%7;
    }
    if(_wday!=0){
        rep(i,_wday,5) put_space(2),putchar('/'),put_space(2),putchar('|');
        put_space(2),putchar('/');
    }
    putchar('n');
}
void calc_wday(struct DATE *Q){
    /* Base on 2020-1-1 Wed. */
    int delta=0,by=2020,bm=1,bd=1;
    /*
    while(by<Q->year){
        delta+=is_leap_year(by)?366:365; 
        by++; i_am_doing();
    }
    while(by>Q->year){
        delta-=is_leap_year(by-1)?366:365; 
        by--; i_am_doing();
    }
    */
    delta+=(Q->year-by)*365;
    delta+=((Q->year-1)/4-(by-1)/4); 
    delta-=((Q->year-1)/100-(by-1)/100);
    delta+=((Q->year-1)/400-(by-1)/400);
    by=Q->year;

    while(bm<Q->mon){
        if(bm==2) delta+=is_leap_year(by)?29:28;
        else delta+=c_day[bm];
        bm++; i_am_doing();
    }
    delta+=Q->day-bd;
    Q->wday=get_wday(3,delta);
}
void Query_Mode(){
    color_change(); CLEAR();
    printf(
        "n%snWelcome to Query-Mode!n"
        "In this mode, you can input a date like this:n"
        "1969 11 9n"
        "And I will show you the monthly calendar of the date.n"
        "Notice not to input an illegal date.n"
        "If, you do that, I may point it out.n"
        "When you want to exit this mode, input three '0':n"
        "0 0 0n"
        "Enjoy your time!n%snn",div_line,div_line
    );
    PAUSE();
    struct DATE Q; 
    while(1){
        color_change(); CLEAR();
        printf("Now tell me what date you want to query:n");
        scanf("%d%d%d",&Q.year,&Q.mon,&Q.day);
        if(Q.day==0&&Q.mon==0&&Q.year==0){
            color_change(); CLEAR();
            printf("n%snThanks for your use!n",div_line);
            printf("Now press any key to exit Query_Mode.n%snn",div_line);
            PAUSE(); return;
        }
        if(legal_judge(&Q)==0){
            printf("You input an illegal date! Try again!n");
            PAUSE();
            continue;
        }else{
            calc_wday(&Q); CLEAR();
            /* display */
            printf("%sn",div_line);
            _display(&Q);
            printf("%sn",div_line);
            /* ask for another */
            printf(
                "I have show you the calendar.n"
                "Now press any key to come back.n"
                "If you want to exit this mode, input '0 0 0' next time.n"
            );
            PAUSE();
        }
    }
    
}

/*----------------------------------------------------------------------------*/

int main(){
    srand(time(NULL));
    _statement();
    while(1){
        time_t sec_; time(&sec_);
        struct tm *p; p=localtime(&sec_);
        struct DATE now; get_date(&now,p);
        /* Display the date today. */
        color_change(); CLEAR();
        printf("Today is a good day!n");
        printf("%sn",div_line);
        _display(&now);
        printf("%sn",div_line);
        /* Ask for next option. */
        printf(
            "What do you want to do now?n"
            "Input an opt as follow to tell me.n"
            "1 - to query some date.n"
            "2 - to fix year.n"
            "3 - to exit.n"
            "If you input something else, n"
            "I will change the color for you.n"
        );
        int opt;
        printf("%snInput option:n",div_line),scanf("%d",&opt);
        if(opt==1) Query_Mode();
        if(opt==2) Fix_Mode();
        if(opt==3){
            color_change(); CLEAR();
            printf("%snSee you next time!n%sn",div_line,div_line);
            PAUSE(); break;
        }
    }
    return 0;
}