Need your help in Making syntax Checker in C++ using stack

[Big papi]

 QUESTION:You are required to write a program that performs syntax checking for a given computer program
  Hey Everyone i need your help badly can anyone please modify my code below

against the following rules:
• The code always starts with begin keyword and ends with the end keyword
• The conditional statements start with if keyword and ends with endif keyword
• There may be zero, one or more elseif within if—endif block
• There may be zero or one else within if—endif block
• There are two kinds of loops: The for loop block ends with endfor, and while loop block
ends with endwhile.
• The brackets must be balanced. The inner brackets must close before the outer brackets.
Following is example of balanced brackets:
/{ { ( ) } ( ) }/
• Following is an example of imbalanced brackets (note the sequence of last two closing brackets):
/{ { ( ) } ( } )/
Your program must check that the given code is free of the following errors:
• begin without end
• end without begin
• if without endif
• elseif without if
• else without if
• endif without if
• for without endfor
• endfor without end
• while without endwhile
• endwhile without while
• Imbalanced {} and () brackets
In case of an error (mismatched keyword or bracket) your program should print an error message,
properly showing the keyword which was mismatched, and the line of code where the mismatch is seen//

#include<iostream>
#include<cstring>
#include<stack>
#include<fstream>

using namespace std;

stack <string> s;

void stk(string m) 
{
    if ( m == "begin" || m == "if" || m == "for" || m == "while" || m == "{" || m == "(" ) 
    {
        s.push(m);
    }

    else if ( m == "elseif" && s.top() == "if" )
    {
        s.push(m);
    }

    else if ( m == "else" && s.top() == "if" )
    {
        s.push(m);
    }

    else if ( m == "endif" ) 
    {
        if ( s.top() != "if" )
        {
            cout << "[WARNING] 'endif' is not allowed withoud 'if'" << endl;
            return;
        }

        else if ( s.top() == "if" )
        {
            s.pop();
        }
    }

    else if ( m == "endfor" )
    {
        if ( s.top() != "for" )
        {
            cout << "[WARNING] 'endfor' is not allowed withoud 'for'" << endl;
            return;
        }

        else if ( s.top() == "for" )
        {
            s.pop();
        }
    }

    else if ( m == "endwhile" )
    {
        if ( s.top() != "while" )
        {
            cout << "[WARNING] 'endwhile' is not allowed without 'while'" << endl;
            return;
        }

        else if ( s.top() == "while" )
        {
            s.pop();
        }
    }

    else if ( m == "}" )
    {
        if ( s.top() != "{" )
        {
            cout << "[WARNING] '}' is not allowed withoud '{'" << endl;
            return;
        }

        else if ( s.top() == "{" )
        {
            s.pop();
        }
    }

    else if ( m == ")" )
    {
        if ( s.top() != "(" )
        {
            cout << "[WARNING] ')' is not allowed withoud '('" << endl;
            return;
        }

        else if ( s.top() == "(" )
        {
            s.pop();    
        }
    }

    else if ( m == "end" )
    {
        if ( s.top() != "begin" )
        {
            cout << "[WARNING] 'end' is not allowed withoud 'begin'";
            system("pause");
            return;
        }

        else if ( s.top() == "begin" )
        {
            s.pop();
        }
    }
}

void syntaxChecker() 
{
    if ( s.empty() == true || s.top() == "elseif" || s.top() == "else") 
    {
        cout << "No syntax error found";
    }

    else if (s.top() == "{" )
    {
        cout << "Expected '}' ";
    }

    else if (s.top() == "(" )
    {
        cout << "Expected ')' ";
    }

    else if (s.top() == "if" )
    {
        cout << "Expected 'endif' ";
    }

    else if (s.top() == "while" )
    {
        cout << "Expected 'endwhile' ";
    }

    else if (s.top() == "for" )
    {
        cout << "Expected 'endfor ";
    }
}

int main ()
{
    //string code;
    //readfile();
    string ch;

    fstream new_file; 
    new_file.open("ENTER FILE ADDRESS HERE",ios::in);  

    if(!new_file) 
    cout<<"No such file"; 
    else 
    { 
    cout<<"File opened successfully!\n\n";

    while (!new_file.eof()) 
    { 
    new_file >>ch; 
    cout << ch;   
    }

    new_file.close();    
    }

    do
    {
        stk(ch);
    }
    while(ch != "end");

    syntaxChecker();
    return 0;
}

I just need to enter a file(TXT) using file handling and then the program will chk whther the code given in file is balanced or not according to above certain conditions. Can anyone kindly enough can do this for me. That will be very helpful