C ++ methods using heavy weights positive binary number is converted to decimal number

#include <the iostream> 
#include <the Windows.h> 
#include < String > the using namespace STD; int main ( void ) {
     String STR;
     int P = . 1 ; // record the current binary weight
     int S = 0 ; 
    COUT << " enter a binary number: " ; 
    CIN >> STR; for ( int I = str.length () - . 1 ; I> = 0 ; i-- ) {
         int X STR = [I] - '

 




    0'; // '0' - '0' = 0  '1' - '0' = 1
        s += x * p;
        p *= 2; // p = p * 2
    }
    cout << s << endl;
    system("pause");
    return 0;
}