The perpetual calendar query program is written in C language.

I revised the part I found on the Internet again. Now it basically meets the requirements of lz.

I don't have Wintc tested by vc at hand, but I haven't used anything unique to vc either. I think so.

# include & ltstdio.h & gt

# include & ltstdlib.h & gt

# include & ltconio.h & gt

void DayOfWeek()

{

int rtnDay

int y，m，d；

char ch

while ( 1)

{

Printf ("Please enter the year, month and day (xxxx, xx, xx):");

scanf("%d，%d，%d "，& ampy & amp； m & amp； d)；

fflush(stdin)；

RTN day =(3 * y-(7 *(y+(m+9)/ 12))/4+(23 * m)/9+d+ 17-((y+(m & lt； 3? - 1:0))/ 100+ 1)*3/4) % 7;

Printf("%04d %02d month %02d day is week %d \n ",y, m, d, rtnDay? RTN day:7)；

Printf ("Continue query (y/n)");

ch = getchar()；

If (ch! = ' y ' & amp& ampch！ = 'Y ')

Break;

}

}

Void GetMonth (integer d, integer md, integer n)

{

int N，m，d，y，c，Wd；

int i，maxday，I 1；

if(MD & gt； = 13 | | MD & lt； =0)

Printf ("Wrong!" );

other

{

for(I 1 = 0； ; md++，i 1++)

{

If (md==0)

{

MD = 12；

d-= 1；

}

other

if(md== 13)

{

MD = 1；

d+= 1；

}

m = md

printf(" \ n = = = = = = = = = = = = = % D，% 2d = = = = = = = = = = = = \ n "，D，MD)；

if(0 & lt； m & amp& ampm & lt= 12)

{

Switch (m)

{

Case1:maxday = 31; Break;

Case 2: If (d% 4 = = 0& & d%100! =0||D%400==0)

maxday = 29

other

maxday = 28

Break;

Case 3: maxday = 31; Break;

Case 4: maxday = 30 breaks;

Case 5: maxday = 31; Break;

Situation 6: maxday = 30; Break;

Case 7: maxday = 31; Break;

Case 8: maxday = 31; Break;

Situation 9: maxday = 30; Break;

Case10: maxday = 31; Break;

Case11:maxday = 30; Break;

Case12: maxday = 31; Break;

Default: printf ("wrong");

}

if(0 & lt； m & amp& ampm & lt=2)

{

n = D- 1；

m = m+ 10；

}

other

{

n = D；

m = m-2；

}

c = N/ 100；

y = N % 100；

wd =(( 1+( 13 * m- 1)/5+y+y/4+c/4-2 * c)% 7+7)% 7；

Printf ("Sun Mou TUR Wednesday Friday Saturday");

for(I = 0； I & ltwd；; i++)

printf("%4c "，' ')；

for(d = 1； d & lt= maxdayd++)

{

printf("%4d "，d)；

Wd =(Wd+ 1)% 7；

If (Wd==0)

printf(" \ n ")；

}

}

other

Printf ("Wrong!" );

if(i 1==n)

Break;

}

}

}

void MonthOfYear()

{

char ch

int y，m；

while ( 1)

{

Printf ("Please enter the year and month (xxxx, xx):");

scanf("%d，%d "，& ampy & amp； m)；

fflush(stdin)；

GetMonth(y，m，0)；

Printf ("\ nContinue query (y/n)");

ch = getchar()；

If (ch! = ' y ' & amp& ampch！ = 'Y ')

Break;

}

}

void GetYear()

{

char ch

int y；

while ( 1)

{

Printf ("Please enter year:");

scanf("%d "，& ampy)；

fflush(stdin)；

GetMonth(y， 1， 1 1)；

Printf ("\ nContinue query (y/n)");

ch = getchar()；

If (ch! = ' y ' & amp& ampch！ = 'Y ')

Break;

}

}

int main()

{

char ch

while( 1)

{

System ("CLS");

Printf(" 1。 Query week \ n ");

Printf("2。 Query month \ n ");

Printf("3。 Display a year \ n ");

Printf("4。 Exit the program \ n ");

ch = getchar()；

fflush(stdin)；

Switch (channel)

{

Case "1":

day ofweek()；

Break;

Case "2":

monthofmyear()；

Break;

Case "3":

GetYear()；

Break;

Case "4":

printf(" Exit(y/n)")；

ch = getchar()；

fflush(stdin)；

if(ch == 'y' || ch == 'Y ')

Exit (0);

Break;

}

}

}

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