问递归上的分割错误

EN

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

int f(int value){
    if(value==1) return 1;
    else if(value%2 == 0) return value/2;
    else return 3*value+1;
}

int g(int value){
   if(value == 0) return 0;
   if (f(value)==1) return 1;
   return 1 + g(f(value));
}

int main(int argc, char *argv[]){
    int nSteps=0;
    istringstream iss(argv[1]);
    int;
    if(!(iss >> num).fail()){
        if(num < 0) cout << "0" << endl;
        else{
            nSteps = g(num);
            cout << "Result: " << nSteps << endl;
        } 
    }
    else{
        cout << "Incorrect line paramaters: ./g n" << endl;
    }
    return 0;
}