title: I'm getting an "Error: string was not declared in this scope"
body: <p>I declare a string parameter inside of a bool function. And when I run the code build messages show me "string was not declare in the scope".</p>
  
  <p>I tried it on code block .. </p>
  
  <pre><code>bool isOkay(char open,char close);
  bool isCheck(string exp);
  
  bool isCheck(string exp){
      stack&lt;char&gt;s;
      int i;
  
      for(i=0;i&lt;exp.length();i++){
          if(exp[i] == '(' || exp[i] == '{' || exp[i] == '['){
              s.push(exp[i]);
          }
          else if(exp[i] == ')' || exp[i] == '}' || exp[i] == ']'){
              if(s.empty() || !isOkay(s.top(),exp[i])){
                  return false;
              }
              else{
                  s.pop();
              }
          }
      }
      return s.empty() ? true : false;
  }
  
  bool isOkay(char open , char close){
      if(open == '(' &amp;&amp; close== ')') return true;
       else if(open == '{' &amp;&amp; close== '}') return true;
        else if(open == '[' &amp;&amp; close== ']') return true;
  
      return false;
  }
  </code></pre>
  
  <p>The error message is "String was not declare in the scope"</p>