Write a program to create a structure named student that has name, roll, mark and remark as members. A program should read and display data entered by the user, except for remark which is set to 'P' if student has secured 40% or more marks in exam, otherwise it is set to 'F'. Assume appropriate data types.

Here is a program that creates a student structure with name, roll, mark, and remark members. The program reads in data from the user, calculates the remark based on the student's marks, and displays all the information back to the user.

#include <iostream>

#include <string>

using namespace std;

struct student {

    string name;

    int roll;

    double mark;

    char remark;

};

int main() {

    student s;

    // Read in student data

    cout << "Enter student name: ";

    getline(cin, s.name);

    cout << "Enter student roll number: ";

    cin >> s.roll;

    cout << "Enter student marks: ";

    cin >> s.mark;

    // Calculate student remark

    if (s.mark >= 40) {

        s.remark = 'P';

    } else {

        s.remark = 'F';

    }

    // Display student data

    cout << "Student name: " << s.name << endl;

    cout << "Roll number: " << s.roll << endl;

    cout << "Marks: " << s.mark << endl;

    cout << "Remark: " << s.remark << endl;

    return 0;

}

In this program, we first define the student structure with name, roll, mark, and remark members. We then declare a variable of type student named s.

Next, we read in the student data using std::cin and std::getline(). We read the name using std::getline() to allow for spaces in the name.

We then calculate the student's remark based on their marks. If the student has 40% or more marks, their remark is set to 'P', otherwise it is set to 'F'.

Finally, we display all the student data back to the user using std::cout.

Here is an example of the program in action:

Enter student name: John Doe

Enter student roll number: 1234

Enter student marks: 75.5

Student name: John Doe

Roll number: 1234

Marks: 75.5

Remark: P