Problem in running program but the code compiles succesfully

[hunter123]

#include <iostream>
#include <cstdlib>

using namespace std;

char LA;
char* str;
void R(int R_i, int& R_s);
void Digit(int& Digit_val);
void input_error();

char token() 
{
     return *str++; 
     }

void Num(int& Num_val)
{
  int Digit_value, R_i, R_s;
  Digit(Digit_value);
  R_i = Digit_value;
  R(R_i,R_s);
  Num_val = R_s;
}

void R(int R_i, int& R_s)
{
  int Digit_value, R1_i,R1_s;
  if ( LA == '\0' ) 
    R_s = R_i;
  else
  {
    Digit(Digit_value);
    R1_i = 3* R_i + Digit_value;
    R(R1_i,R1_s);
    R_s = R1_s;
  }
}

void Digit(int& Digit_val)
{
  LA = token();
  if ( LA == '0' ) Digit_val = 1;
  else if ( LA == '1' ) Digit_val = 0;
  else if ( LA == '\0' ) return;
  else input_error();
}


void input_error() 
{ cout << "unacceptable character" << endl; }

int main(int argc, char *argv[])
{ 
  str = argv[1];
  int str_value;
  cout << str << endl;  
  Num(str_value);
  cout << "value = " << str_value << endl;
}

[Ganon11]

Do you want to tell us what this program does? What is should do? Where the error is? Or should we just guess based on the code you've posted?

[hunter123]

Do you want to tell us what this program does? What is should do? Where the error is? Or should we just guess based on the code you've posted?

it solves the SDT(syntax directed translation)
we have to solve
Num -> Digit Num.val := Digit.val
Num -> Num1 Digit Num.val := 3*Num1.val + D.val
Digit -> 0 Digit.val := 1
Digit -> 1 Digit.val := 0
i have written this program it compiles succesful but when i try it to run my Dev C++ compiler says "Program stop working" i think there might be linking error

[r035198x]

Put some cout statements to decide when the error is being given.
e.g in your main you are assuming that argv will have at least 2 entries because you are accessing argv[1]. Are you sure that it has at least 2 entries?

[hunter123]

Put some cout statements to decide when the error is being given.
e.g in your main you are assuming that argv will have at least 2 entries because you are accessing argv[1]. Are you sure that it has at least 2 entries?

i figured ........now its working