C Program To Find Number Of Days Between Two Dates

#include<stdio.h>
#include<math.h>
void main()
{
int day1,mon1,year1,day2,mon2,year2;
int ref,dd1,dd2,i;
clrscr();
printf("\nEnter first day, month, year");
scanf("%d%d%d",&day1,&mon1,&year1);
printf("\nEnter second day,month,year");
scanf("%d%d%d",&day2,&mon2,&year2);
ref = year1;
if(year2<year1)
ref = year2;
dd1=0;
dd1=func1(mon1);
for(i=ref;i<year1;i++)
{
    if(i%4==0)
    dd1+=1;
}
dd1=dd1+day1+(year1-ref)*365;
printf("\nNo. of days of first date fronm the Jan 1 %d= %d",year1,dd1);
/* Count for additional days due to leap years*/
dd2=0;
for(i=ref;i<year2;i++)
{
    if(i%4==0)
    dd2+=1;
}
dd2=func1(mon2)+dd2+day2+((year2-ref)*365);
printf("\nNo. of days from the reference year's first Jan = %d",dd2);
printf("\nTherefore, diff between the two dates is %d",abs(dd2-dd1));

getch();
}




int func1(x)       //x for month y for dd
{  int y=0;
switch(x)
{
case 1: y=0; break;
case 2: y=31; break;
case 3: y=59; break;
case 4: y=90; break;
case 5: y=120;break;
case 6: y=151; break;
case 7: y=181; break;
case 8: y=212; break;
case 9: y=243; break;
case 10:y=273; break;
case 11:y=304; break;
case 12:y=334; break;
default: printf("Error encountered"); exit(1);
}
return(y);
}

Sample Output :
Enter first day, month, year29 7 2009
Enter second day,month,year12 12 2009
No. of days of first date fronm the Jan 1 2009= 210
No. of days from the reference year's first Jan = 346
Therefore, diff between the two dates is 136