Ok, my book said I can use the following formula to calculate the days between two dates.

N = 1461 x f(year, month) / 4 + 153 g(month /5 + day

where

f(year,month) = year-1 if month <=2

year otherwise

g(month) = month + 13 if month <=2

month +1 otherwise

But then it saids this formula only works for dates after March1, 1900( 1 must be added for dates form March 1, 1800 to February 28, 1900 and2 must be added for dates between March 1, 1700 to February 28, 1800

Now I have to write a program that permits the user to typein two dates and then calculates the number of elapsed days.

Ok this is what I have so far.

Code:#include <stdio.h>Code:`int main () { struct date { int month; int day; int year; }; struct date d1, d2, N, N1, N2, x; int daynumber(struct date d); int elapsedDays; int days_between(struct date d1, struct date d2); printf ("Enter date 1 (MM/DD/YYYY): "); scanf ("%d/%d/%d", &d1.month, &d1.day, &d1.year); printF("\n"); if ( d1.month <= 2 ) //suppose to be something with f(year, month). // if( month <= 2){ // f(year, month) = year - 1; g(month) = month + 13; { int year = d1.year - 1; int month = d1.month + 13; } else { year = d1.year; month = d1.month + 1; } printf ("Enter date 2 (MM/DD/YYYY): "); scanf ("%d/%d/%d", &d2.month, &d2.day, &d2.year); printF("\n"); if ( d2.month <= 2 ) { year = d2.year - 1; month = d2.month + 13; ?} else { year = d2.year; month = d2.month + 1; } if( d1 >= 03/01/1800 && d1 <= 02/28/1900) { N = N+1; } else if( d1 >= 03/01/1700 && d1 <= 02/28/1800) { N = N+2; } if( d2 >= 03/01/1800 && d2 <= 02/28/1900) { N = N+1; } else if( d2 >= 03/01/1700 && d2 <= 02/28/1800) { N = N+2; } // Computes N int daynumber(struct date d) { N1 = 1461 * f(d1.year,d1.month) / 4 + 153 * g(d1.month) / 5 + d1.day; N2 = 1461 * f(d2.year,d2.month) / 4 + 153 * g(d2.month) / 5 + d2.day; } // Computes elapsed days between two dates int days_between(struct date d1, struct date d2) { elapsedDays = N2 - N1; return elapsedDays; } // Function to determine if date d is before date x int isbefore(struct date d, struct date x); int isbefore(struct date d, struct date x) { if ( d < x ) x = 1; else x = 0; return x; } printf ("There are %d days between %d/%d/%d and %d/%d/%d", elapsedDays, d1.month, d1.day, d1.year, d2.month, d2.day, d2.year); printF("\n"); return 0; }`

I can not get pass compiling the Program. I pretty new at this and can not figure out my mistakes

Any help will be appreciated, Thanks, Bill