Pointers and const#

Rule: ✅ const binds to left side; if none, binds to right.

---

1) Pointer to const (data const)#

int a=10,b=20;
const int *p = &a;

• can change pointer ✅
• cannot change data through p ❌

p = &b;   // ✅
*p = 5;   // ❌

---

2) Const pointer (pointer const)#

int * const p = &a;

• cannot change pointer ❌
• can change data ✅

*p = 5;  // ✅
p = &b;  // ❌

---

3) Const pointer to const data#

const int * const p = &a;

Both cannot change.

---

Summary table#

Declaration	Change pointer?	Change data?
const int *p	✅ yes	❌ no
int *const p	❌ no	✅ yes
const int *const p	❌ no	❌ no

---

Reading trick (right to left)#

• int * const p → p is const pointer to int
• const int * p → p is pointer to const int