10473 - Simple Base Conversion

#include<stdio.h>
int main()
{
int n,l;
char num[15];
//freopen("in.txt","r",stdin);

while(true)
{
gets(num);
for(l=0;num[l];l++);

if(l>=2)
{
if(num[1]=='x')
{
sscanf(num,"%X",&n);
printf("%d\n",n);
}
else
{
sscanf(num,"%d",&n);
if(n<0)break;
printf("0x%X\n",n);
}
}
else
{
sscanf(num,"%d",&n);
if(n<0)break;
printf("0x%X\n",n);
}
}
return 0;
}