arrow operator c++
// C program to show Arrow operator
// used in structure
#include <stdio.h>
#include <stdlib.h>
// Creating the structure
struct student {
char name[80];
int age;
float percentage;
};
// Creating the structure object
struct student* emp = NULL;
// Driver code
int main()
{
// Assigning memory to struct variable emp
emp = (struct student*)
malloc(sizeof(struct student));
// Assigning value to age variable
// of emp using arrow operator
emp->age = 18;
// Printing the assigned value to the variable
printf("%d", emp->age);
return 0;
}
/*
the arrow operator is used for accessing members (fields or methods)
of a class or struct
it dereferences the type, and then performs an element selection (dot) operation
*/
#include <iostream>
using std::cout;
class Entity {
public:
const char* name = nullptr;
private:
int x, y;
public:
Entity(int x, int y, const char* name)
: x(x), y(y), name(name) {
printEntityPosition(this); // "this" just means a pointer to the current Entity
}
int getX() { return x; }
int getY() { return y; }
friend void printEntityPosition(Entity* e);
};
// accessing methods using arrow
void printEntityPosition(Entity* e) {
cout << "Position: " << e->getX() << ", " << e->getY() << "\n";
}
int main() {
/* ----- ARROW ----- */
Entity* pointer = new Entity(1, 1, "Fred");
//printEntityPosition(pointer); redacted for redundancy (say that 5 times fast)
cout << (*pointer).name << "\n"; // behind the scenes
cout << pointer->name << "\n"; // print the name (with an arrow)
/* ----- NOT ARROW ----- */
Entity not_a_pointer(2, 2, "Derf");
//printEntityPosition(¬_a_pointer); & to convert to pointer
cout << not_a_pointer.name << "\n"; // print the name (with a dot)
/* ----- LITERALLY NEITHER ----- */
std::cin.get(); // wait for input
return 0; // exit program
}