Hi there,

I am implementing simple student class when i run the program it crashes after getting input for char* name. Program is as follows.

#include <iostream>

using namespace std;

class Student
{
    private:

        char* name;
        int rollNo;
        float cgpa;

    public:

        Student()
        {
            name = "";
            rollNo = 0;
            cgpa = 0.0;
        }

        void setName()
        {
            cout<<"Enter name : "<<flush;   //after input my program crashes
            cin >> name;
        }

        void setName(char* newName)
        {
            name = newName;
        }

        char* getName()
        {
            return name;
        }

        void setRollNo()
        {
            cout<<"Enter roll no : "<<flush;
            cin >> rollNo;
        }

        void setRollNo(int newRollNo)
        {
            rollNo = newRollNo;
        }

        int getRollNo()
        {
            return rollNo;
        }

        void setCgpa()
        {
            cout<<"Enter cgpa : "<<flush;
            cin >> cgpa;
        }

        void setCgpa(float newCgpa)
        {
            cgpa = newCgpa;
        }

        float getCgpa()
        {
            return cgpa;
        }
};

int main()
{

    Student s1;

    //s1.setName("Ahmad");
    s1.setName();
    cout<<"Name :\t\t"<<s1.getName() <<endl;
    //s1.setRollNo(23);
    s1.setRollNo();
    cout<<"Roll no :\t" <<s1.getRollNo() <<endl;
    //s1.setCgpa(3.45);
    s1.setCgpa();
    cout<<"Cgpa :\t\t" <<s1.getCgpa() <<endl;

    return 0;
}

Please see the comment where my program crashes, I don't know why ? Please help and explain, I am using Code Blocks. Thanks.

Your problem lies in line 17:

name = "";

Your name attribute is initialized to a read only memory having name to point to that memory location, but any writing is illigal, thus your error. If you would initialize name as this:

name = new char[200];

you would allocate memory on the heap, making writing legal for that variable, e.g. the cin part.

Also, why are you using C-style strings (null terminated sequences of characters) for names? Wouldn't std::string(Click Here) suite you better?

Edited 3 Years Ago by Lucaci Andrew

To add a little to Lucaci's words, any string in your code you make like this: "some letters" is a string literal. It is for reading only. Trying to write to that memory is forbidden. Look up string literal for all the details.

What all these good people said. In any case, your compiler should have emitted a warning that your were initializing a non-const string to a const char* "". DO NOT disable compiler warnings, unless you really know what you are doing!

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