Ошибка компиляции

#include "stdafx.h"
#include <iostream>
#include <string>
 
using namespace std;
 
class GradeBook
{
public:
    GradeBook( string name )
    {
        setCourseName( name );
    }
    
    void setCourseName( string name )
    {
        courseName = name;
    }
 
    string getCouseName()
    {
        return courseName;
    }
    
    void displayMsg()
    {
        cout << "Wellcome To Grade Book for " << getCourseName() << "!" << endl;
    }
 
private: string courseName;
};
 
int main()
{
    GradeBook myGrade1( "CS11 C++" );
    GradeBook myGrade2( "CS11 C#" );
 
    cout << "First Grade Book created for: " << myGrade1.getCourseName() << "\nTwo Grade book created for: " << myGrade2.getCourseName() << endl;
    
    system("pause");
    
    return 0;
}

#include <iostream>
#include <string>
 
using namespace std;
 
class GradeBook
{
public:
    GradeBook( string name )
    {
        setCourseName( name );
    }
    
    void setCourseName( string name )
    {
        courseName = name;
    }
 
    string getCouseName()
    {
        return courseName;
    }
    
    void displayMsg()
    {
        cout << "Wellcome To Grade Book for " << getCouseName() << "!" << endl;
    }
 
private: string courseName;
};
 
int main()
{
    GradeBook myGrade1( "CS11 C++" );
    GradeBook myGrade2( "CS11 C#" );
 
    cout << "First Grade Book created for: " << myGrade1.getCouseName() << "\nTwo Grade book created for: " << myGrade2.getCouseName() << endl;
    
    system("pause");
    
    return 0;
}

main.cpp:39:16: error: 'system' was not declared in this scope

#include <iostream>
#include <cstdlib>
#include <string>
 
using namespace std;
 
class GradeBook
{
public:
    GradeBook( string name )
    {
        setCourseName( name );
    }
    
    void setCourseName( string name )
    {
        courseName = name;
    }
 
    string getCouseName()
    {
        return courseName;
    }
    
    void displayMsg()
    {
        cout << "Wellcome To Grade Book for " << getCouseName() << "!" << endl;
    }
 
private: string courseName;
};
 
int main()
{
    GradeBook myGrade1( "CS11 C++" );
    GradeBook myGrade2( "CS11 C#" );
 
    cout << "First Grade Book created for: " << myGrade1.getCouseName() << "\nTwo Grade book created for: " << myGrade2.getCouseName() << endl;
    
    system("pause");
    
    return 0;
}

GradeBook( string name ) courseName(name) {}

GradeBook( string name ) : courseName(name) {}