What should be the potential reason to get runtime error for this program?
- by MiNdFrEaK
#include<iostream>
#include<stack>
#include<vector>
#include<string>
#include<fstream>
#include<cstdlib>
/*farnaws,C++,673,08/12/2012*/
using namespace std;
    string verifier(string input_line)
    {
        stack <char> braces;
        for(int i=0; i<input_line.size(); i++)
        {
            if(input_line[i]=='(' || input_line[i]=='[')
            {
                braces.push(input_line[i]);
            }
            else if(input_line[i]==')' || input_line[i]==']')
            {
                braces.pop();   
            }
        }
        if(braces.size()==0)
        {
             return "YES";      
        }
        else
        {   
             return "NO";   
        }
    }
    int main()
    {
       ifstream file_input("input.in"); 
       string read_file;
       vector<string> file_contents;
       if(file_input.is_open())
       {
            while(file_input>>read_file)
            {
                file_contents.push_back(read_file);     
            }
       }
       else
       {
            cout<<"File cant be open!"<<endl;   
       }
        int limit=atoi(file_contents[0].c_str());
        //cout<< limit;
       ofstream file_output("output.out");
       if(file_output.is_open())
       {
            for(int i=1; i<=limit; i++ )
            {
                file_output<<verifier(file_contents[i])<<endl;
            }
       }
       else
       {
            cout<<"File cant be open!"<<endl;   
       }
       return 0;
    }