Base Converting

#include<stdio.h> //program to convert base
main()
{
    char digits[16]={'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};
    int store[64];
    int i=0,base,n,no;
    printf("Enter your number: ");
    scanf("%d",&n);
    printf("Enter your base: ");
    scanf("%d",&base);
    do
    {
        store[i]=n%base;
        i++;
        n/=base;
    } while (n);
//the problem is everytime i becomes "-1", when it should have become "i-1"
    for(--i;i>=0;i--);
    {
        printf("%c",digits[store[i]]);
    }
}