comefrom: <awangdev>43. Multiply Strings_4.java
code: private int toInt(String s, int x) {
  
          return s.charAt(x) - '0';
      }
masked: private int sample_funcname ( String var_0 , int var_1 ) {
    return var_0 . charAt ( var_1 ) - '0' ;
  }
  