pointer | Sololearn: Learn to code for FREE!
Новый курс! Каждый программист должен знать генеративный ИИ!
Попробуйте бесплатный урок
+ 5


can anyone explain pointer!

21st Oct 2016, 8:19 AM
F.Heeh. 2nd Yr. Hebron University‏‎
F.Heeh. 2nd Yr. Hebron University‏‎ - avatar
2 ответов
+ 4
it would be really useful for me if you explain it more in examples if possible!
21st Oct 2016, 8:20 AM
F.Heeh. 2nd Yr. Hebron University‏‎
F.Heeh. 2nd Yr. Hebron University‏‎ - avatar
+ 2
A pointer contain an address. You can dereference a pointer to access the value pointed. Example (in C++): int ans = 42; //Declaration of a int * variable, assignment of the address of ans to it //The * here is NOT the dereferencing operator, but is part of the type: int * indicates that this is a pointer pointing to an int //& is the address-of operator int *ptr = &ans; cout << *ptr << endl; //dereferences ptr and prints 42 //Changing the value of ans changes the value of *ptr //and vice versa (they both refer to the same memory space) ans = 43; cout << *ptr << endl; //prints 43 Since pointers just contain an address, if you have a big object and want to pass it as an argument to a function, it is better to pass a pointer to that object instead. Same deal for returned values. You can also use a reference to pass big objects to a functions. References are like pointers in that they contain an address, but they must reference a variable (while you can set a pointer's value to whatever you want), and there is no need to dereference them. They are like an alias of the variable. The changes operated by a pointer or reference can persist between function calls. For example, here is a function that takes two references as parameters and swap the value of the two variables (& here is NOT the address-of operator, it indicates that the value is a reference): //Swaps the value of two variables void swap(int &a, int &b) { int tmp = a; a = b; b = tmp; }
21st Oct 2016, 10:59 AM
Zen - avatar