C program to read, display add and subtract two distances. Distance must be defined using kms and meters

#include <stdio.h>
#include <conio.h>
typedef struct distance
{
	 int kms;
int meters;
}DISTANCE;
DISTANCE add_distance (DISTANCE, DISTANCE);
DISTANCE subtract_distance (DISTANCE, DISTANCE);
DISTANCE d1, d2, d3, d4;
int main()
{
int option;
	 clrscr();
do
{
	 	 printf("\n ******** MAIN MENU *********");
	 	 printf("\n 1. Read the distances ");
	 	 printf("\n 2. Display the distances");
	 	 printf("\n 3. Add the distances");
	 	 printf("\n 4. Subtract the distances");
	 	 printf("\n 5. EXIT");
	 	 printf("\n Enter your option : ");
	 	 scanf("%d", &option);
	 	 switch(option)
 {
	 	 	 case 1:
	 	 	 	 printf("\n Enter the first distance  in kms and meters: ");
	 	 	 	 scanf("%d %d", &d1.kms, &d1.meters);
	 	 	 	 printf("\n Enter the second distance  in kms and meters: ");
	 	 	 	 scanf("%d %d", &d2.kms, &d2.meters);
	 	 	 	 break;
	 	 	 case 2:
	 	 	 	 printf("\n The first distance is : %d kms %d meters",
d1.kms, d1.meters);
	 	 	 	 printf("\n The second distance is : %d kms %d meters",
d2.kms, d2.meters);
	 	 	 	 break;

case 3:
	 	 	 	 d3 = add_distance(d1, d2);
	 	 	 	 printf("\n The sum of two distances is : %d kms %d
meters", d3.kms, d3.meters);
	 	 	 	 break;
	 	 	 case 4:
	 	 	 	 d4 = subtract_distance(d1, d2);
	 	 	 	 printf("\n The difference between two distances is : %d
kms %d meters", d4.kms, d4.meters);
	 	 	 	 break;
 }
	 }while(option != 5);
	 getch();
	 return 0;
}
DISTANCE add_distance(DISTANCE d1, DISTANCE d2)
{
	 DISTANCE sum;
sum.meters = d1.meters + d2.meters;
	 sum.kms = d1.kms + d2.kms;
	 while (sum.meters >= 1000)
{
	 	 sum.meters = sum.meters % 1000;
	 	 sum.kms += 1;
}
return sum;
}
DISTANCE subtract_distance(DISTANCE d1, DISTANCE d2)
{
	 DISTANCE sub;
	 if(d1.kms > d2.kms)
{
 sub.meters = d1.meters – d2.meters;
	 	 sub.kms = d1.kms – d2.kms;
}
else
{
 sub.meters = d2.meters – d1.meters;
	 	 sub.kms = d2.kms – d1.kms;
}
	 if(sub.meters < 0)
{
	 	 sub.kms = sum.kms – 1;
	 	 sub.meters = sum.meters + 1000;
}
return sub;
}

******** MAIN MENU *********
1. Read the distances
2. Display the distances
3. Add the distances
4. Subtract the distances
5. EXIT
Enter your option : 1
Enter the first distance in kms and meters: 5 300
Enter the second distance in kms and meters: 3 400
Enter your option : 3
The sum of two distances is: 8 kms 700 meters
Enter your option : 5