Your header file with class student_Example doesn’t promise a constructor. (And seems to be missing and #endif)
#ifndef STUDENT_EXAMPLE_H
#define STUDENT_EXAMPLE_H
#include <iostream>
#include <string>
class student_Example
{
public:
student_Example(char nam, int marc1, int marc2); //<-- as pointed out in the error
char name;
int mark1, mark2;
int calc_media(){
return (mark1+mark2/2);
}
void disp(){
std::cout<< " The student named: "<< name<< "\n has an average score equal to: " << calc_media()<<"\n";
}
};
#endif //<-- this too
While we are there we can use an member initialiser list in the constructor
student_Example::student_Example(char nam, int marc1, int marc2) :
name(nam),
mark1(marc1),
mark2(marc2) //assume maerc2 was a typo
{
}
Edit: Note that student_Example(char nam, int marc1, int marc2) is a declaration that you will define a constructor taking a char and two ints., which you have done in your cpp file.
You can make an object like this
student_Example example('n', 1, 2);
Without this non-default constructor, a default constructor taking no parameters would have been automatically generator for you, so you could have made an object like this:
student_Example example;
Now you have defined a constructor that will no longer happen. You either need to add this to your class, or make sure you use the constructor taking parameters.