If 10 as input then 9 is printed as output. We use while in program to obtain the digits of a number. To invert number look at it and write it from opposite direction or the output of code is a number obtained by writing original number from right to left. To reverse or invert large numbers use long data type or long long data type if your compiler supports it, if you still have large numbers then use strings or other data structure.
//Print no. in reverse order with diff. of two
#include<stdio.h>
#include<conio.h>
void main()
{
int i=10;
while(i>=2)
{
printf("%d",i);
i=i-2;
printf("\n");
getch();
}
}
10
8
6
4
2