language: C++ 4.7.2 (gcc-4.7.2)
date: 861 days 20 hours ago
link:
visibility: public 
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#include <iostream>
#include <sstream>
 
using namespace std;
 
std::string ToString(long v)
{
    std::ostringstream ss;
    ss << v;
    return ss.str();
}
//convert string to long
long FromString(const std::string& str)
{
    std::istringstream ss(str);
    long ret;
    ss >> ret;
    return ret;
}
bool IsNumber(const std::string &str)
{
    //try converting string to long, and then back to string again!
    string value = ToString(FromString(str));
    //check if these two strings are exactly same!
    return value == str;
}
 
 
int main() 
{
    bool ret;
 
    ret = IsNumber("1809839");
    cout << ret << endl;
    ret = IsNumber("180hj9839");
    cout << ret << endl;
}