#include <iostream>


union Data {

  int i;

  float f;

  char c;

};


int main() {

  // Declare a variable of type Data

  Data data;


  // Assign a value to the integer member of the Data union

  data.i = 5;

  std::cout << "The value of the integer member is " << data.i << std::endl;


  // Assign a value to the float member of the Data union

  data.f = 3.14;

  std::cout << "The value of the float member is " << data.f << std::endl;


  // Assign a value to the char member of the Data union

  data.c = 'A';

  std::cout << "The value of the char member is " << data.c << std::endl;


  return 0;

}

output : 

The value of the integer member is 5
The value of the float member is 3.14
The value of the char member is A