Mobile Casanova

#include <iostream>
#include <cstdio>
#include <string>
#include <cstring>
#include <algorithm>
#include <vector>
#include <cmath>
#include <queue>

using namespace std;

const char* num2str(long long n)
{
    int i, j = 0;
    char str[15];
    do{
        int k = n%10;
        str[j++] = (k+'0');
        n/=10;
    }while(n);
    str[j++] = ('0');
    str[j] = ('\0');
    reverse(str, str+j);
    return str;
}

int main()
{
    //freopen("in.txt", "r", stdin);
    long long i, j, n, k, kase = 1;;
    vector<long long>v;
    char str[15];

    while(scanf("%lld", &n) && n){
        i = n;
        while(i--){
            scanf("%s", str);
            k = strtoll(str, NULL, 10);
            v.push_back(k);
        }
        //sort(v.begin(), v.end());
        //n = v.size();
        printf("Case %d:\n", kase++);
        int st, fn;
        for(i = 0; i < n; i++){
            st = v[i];
            while((i < n-1) && (v[i]+1 == v[i+1])){
                i++;
            }
            fn = v[i];
            if(st == fn){
                char s[15];
                strcpy(s, num2str(st));
                printf("%s\n", s);
            }
            else{
                char start[15], finish[15];
                strcpy(start, num2str(st));
                strcpy(finish, num2str(fn));

                j = 0;
                while(start[j] == finish[j])
                    putchar(start[j++]);

                k = j;
                while(start[j] != '\0')
                    putchar(start[j++]);

                putchar('-');

                while(finish[k] != '\0')
                    putchar(finish[k++]);

                putchar('\n');
            }
        }
        printf("\n");
        v.clear();
    }
    return 0;
}