UVA11541 Decoding

#include <iostream>
#include <string>
using namespace std;

int main() {
int n,num;
char chr;
string str;
while(cin>>n){
for(int t=1;t<=n;++t){
cin>>str;
num=0;
cout<<"Case "<<t<<": ";
for(int i=0;i<str.length();++i){
if(str[i]>='A' && str[i]<='Z'){
while(num){
num--;
cout<<chr;
}
chr=str[i];
}else if(str[i]>='0' && str[i]<='9'){
num*=10;
num+=(str[i]-'0');
}
}
while(num){
num--;
cout<<chr;
}
cout<<endl;
}
}
return 0;
}