Solving for the date and days passed via functions - c

Question

I'm getting better in my C coding but I'm still unsure how to solve several problems in my code. The professor wants us to write a code where we input the day (mm/dd/yyyy) and spits out the number of days that have passed. For choice 2, input number of days in a certain year and spits out the corresponding date. The problem is (since our prof likes to mess with us) solving for errors like 4/31/2001 where April doesn't have 31 days and inputing 366 days in a non-leap year.
int leap(int x)
{
if ((x % 4 == 0 && x % 100 != 0)|| x % 400 == 0)
return 1;
else
return 0;
}
int monthFun(int d, int y)
{
int days[] = {31,28,31,30,31,30,31,31,30,31,30,31};
int i;
if (leap(y))
days[1] = 29;
for (i = 0; ; i++)
if (d > days[i])
d = d - days[i];
else
return i + 1;
return i + 1;
}
int dateFun(int d, int y)
{
int days[] = {31,28,31,30,31,30,31,31,30,31,30,31};
int i, m;
if (leap(y))
days[1] = 29;
for (i = 0; i < m - 1; i++)
if (d > days[i]) {
d = d - days[i];
}
else {
d = d;
m = i;
}
return d;
}
int daysPast(int m, int d, int y)
{
int days[] = {31,28,31,30,31,30,31,31,30,31,30,31};
int i, past = 0;
if (leap(y))
days[1] = 29;
for (i = 0; i < m - 1; i++)
past = past + days[i];
return past + d;
}
int main()
{
int mm, dd, yy, choice;
char more;
do {
printf ("\n\t\tThis program will find days passed or date in the year");
printf ("\n\t\t\t\t1) Input date (mm/dd/yyyy) to find the days passed");
printf ("\n\t\t\t\t2) Input passed days to find date in the year");
printf ("\n\n\t\t\t\tYour choice (1/2): ");
scanf ("%d", &choice);
if (choice == 1) {
printf ("\n\t\tPlease input date (mm/dd/yyyy): ");
scanf ("%d/%d/%d", &mm, &dd, &yy);
printf ("\n\t\tThere are %d days passed in the year %d", daysPast(mm, dd, yy), yy);
}
else
if (choice == 2){
printf ("\n\t\tInput days: ");
scanf ("%d", &dd);
printf ("\n\t\tInput year: ");
scanf ("%d", &yy);
printf ("\n\t\tThe date is %d/%d/%d", monthFun(dd, yy), dateFun(dd,yy), yy);
}
else
printf ("\n\t\tPlease choose 1 or 2");
printf ("\n\n\t\tDo more (Y/N)? ");
scanf ("%s", &more);
} while (more == 'y' || more == 'Y');
}
The code for my dateFun() is a little sloppy (or at least seems like it to me). I figured that if one of the aforementioned problems is entered, the program says something like "invalid input" and takes you back to "do more". Any tips are appreciated and thanks in advance!

Answer 1

Your dateFun tests an uninitialized m.
dateFun() and monthFun() are looking very similar, I've added a sample combined version.
int leap(int x)
{
return ((x % 4 == 0 && x % 100 != 0)|| x % 400 == 0);
}
int monthFun(int d, int y)
{
int i, days[] = {31,28,31,30,31,30,31,31,30,31,30,31};
days[1] += leap(y);
for (i=0 ; d>days[i] ; i++)
d -= days[i];
return i+1;
}
int dateFun(int d, int y)
{
int i, days[] = {31,28,31,30,31,30,31,31,30,31,30,31};
days[1] += leap(y);
for (i=0 ; d>days[i] ; i++)
d -= days[i];
return d;
}
int datemonthFun(int d, int y)
{
int i, days[] = {31,28,31,30,31,30,31,31,30,31,30,31};
days[1] += leap(y);
for (i=0 ; d>days[i] ; i++)
d -= days[i];
return (i+1)*100+d;
}