I'm getting an "Error: string was not declared in this scope"

Question

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".

I tried it on code block ..

bool isOkay(char open,char close);
bool isCheck(string exp);

bool isCheck(string exp){
    stack<char>s;
    int i;

    for(i=0;i<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 == '(' && close== ')') return true;
     else if(open == '{' && close== '}') return true;
      else if(open == '[' && close== ']') return true;

    return false;
}

The error message is "String was not declare in the scope"

Please read [Why should I not #include ?](https://stackoverflow.com/questions/31816095/why-should-i-not-include-bits-stdc-h). Also my question had two parts. Show a [mcve] as required here please. — πάντα ῥεῖ, Jun 16 '19 at 06:03

Faruk Hossain · Answer 1 · 2019-06-16T06:15:01.337

-2

You didn't add using namespace std; in your program. I compiled it successfully in codeblocks after adding using namespace std; .

Here is the full code:

#include <iostream>
#include <string>
#include <stack>

using namespace std; // May be you didn't write this line.

bool isOkay(char open,char close);
bool isCheck(string exp);

int main() {
    // main func code goes here

    return 0;
}

bool isCheck(string exp){
    stack<char>s;
    int i;

    for(i=0;i<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 == '(' && close == ')') return true;
     else if(open == '{' && close == '}') return true;
      else if(open == '[' && close == ']') return true;

    return false;
}

edited Jun 16 '19 at 06:15

answered Jun 16 '19 at 06:08

Faruk Hossain

1,205
5
12

1

Stop encouraging to use `#include `or `using namespace std;` please. – πάντα ῥεῖ Jun 16 '19 at 06:10
Yeah, as it covers most of the headerfiles so one won't understand the actual headerfile. But as he used it so I provided it. Thank you. – Faruk Hossain Jun 16 '19 at 06:12
_"Yeah, as it covers most of the headerfiles ..."_ It's not even guaranteed to be present with any c++ compiler. – πάντα ῥεῖ Jun 16 '19 at 06:14
Thank you ... Now it's compile successfully – tithidey Jun 16 '19 at 06:16
It is not a standard header file of GNU C++ library. So, if we try to compile our code with some compiler other than GCC it might fail; e.g. MSVC do not have this header. – Faruk Hossain Jun 16 '19 at 06:18
2

@tithidey Again, I strongly recommend you to read [this](https://stackoverflow.com/questions/31816095/why-should-i-not-include-bits-stdc-h) and [this](https://stackoverflow.com/questions/1452721/why-is-using-namespace-std-considered-bad-practice). – πάντα ῥεῖ Jun 16 '19 at 06:33
Hey I have read this two articles. Now I understand why I should not use bits/stdc++. – tithidey Jun 17 '19 at 13:04

I'm getting an "Error: string was not declared in this scope"

1 Answers1