C code review shows entered two years difference days

This C code shows how shows entered two years difference days. And code is helpful while user is in between date manipulation task.

code:

//Tested Ok in Code::Blokcs IDE 17.12
//Pgm shows entered two years difference days.

#include<stdio.h>
#include <stdlib.h>
#include<math.h>

int func1(int x);

void main()
{
    int day1,mon1,year1,day2,mon2,year2;
    int ref,dd1,dd2,i;
//    clrscr();
    printf("\nEnter first year data: dd/mm/yyyy: \n\t");
    scanf("%d/%d/%d",&day1,&mon1,&year1);
    printf("\nEnter second year data: dd/mm/yyyy: \n\t");
    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 from 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\n",abs(dd2-dd1));

    getchar();
}

int func1(int 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("\nError encountered");
        exit(1);
    }
    return(y);
}

//end of program

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