Why Programmer/Developer need to know about dangiling pointer and memory leak?

Answer:

Pointer helps to create user defined scope to a variable, which is called Dynamic variable. Dynamic Variable can be single variable or group of variable of same type (array) or group of variable of different types (struct). Default local variable scope starts when control enters into a function and ends when control comes out of that function. Default global vairable scope starts at program execution and ends once program finishes.

But scope of a dynamic variable which holds by a pointer can start and end at any point in a program execution, which has to be decided by a programmer. Dangling and memory leak comes into picture only if a programmer doesnt handle the end of scope.




Memory leak will occur if a programmer, doesnt write the code (free of pointer) for end of scope for dynamic variables. Any way once program exits complete process memory will be freed, at that time this leaked memory also will get freed. But it will cause a very serious problem for a process which is running long time.

Once scope of dynamic variable comes to end(freed), NULL should be assigned to pointer variable. Otherwise if the code wrongly accesses it undefined behaviour will happen. So dangling pointer is nothing but a pointer which is pointing a dynamic variable whose scope is already finished