Example 1
#include <iostream>
using namespace std;
 
enum Level {
  LOW,
  MEDIUM,
  HIGH
}; 

int main() {
  enum Level myVar = MEDIUM;
  cout << myVar;
  return 0;
}


Example 2
#include <iostream>
#include <string>
using namespace std;

int main() {

  struct STUDENT{
    string id;
    string name;
    float marks[3];
  };
  
  STUDENT std1;
  
  std1.id ="s123456";
  std1.name = "Mary Lam";
  std1.marks[0]=71;
  std1.marks[1]=77;
  std1.marks[2]=79;
  
  cout<<"Average mark of "<<std1.name<<"("<<std1.id<<") = ";
  cout<<(std1.marks[0]+std1.marks[1]+std1.marks[2])/3;

  return 0;
}

Example 3
#include <iostream>
#include <string>
using namespace std;

struct Car{
    string brand;
    string model;
    int year;
};
  
int main() {

  Car CarArray[10];
  // Put data into the first structure
  CarArray[0].brand = "BMW";
  CarArray[0].model = "X5";
  CarArray[0].year = 1999;

  // Put data into the second structure
  CarArray[1].brand = "Ford";
  CarArray[1].model = "Mustang";
  CarArray[1].year = 1969;

  // Print the structure members
  cout << CarArray[0].brand << " " << CarArray[0].model;
  cout << " " << CarArray[0].year << "\n";
  cout << CarArray[1].brand << " " << CarArray[1].model;
  cout << " " << CarArray[1].year << "\n";
  return 0;
}