Help in Pointer

[am_abbas]

Hi There,

int *i,t;

i=(int *) &t; // What does this statement means.... where we use it.

Thanks and Regards,
Abbas

[Gabriel Fleseriu]

Originally posted by am_abbas
Hi There,

int *i,t;

i=(int *) &t; // What does this statement means.... where we use it.

Thanks and Regards,
Abbas

That's a type cast. Totally useless because it casts an int * to int *.

[Bob Davis]

Gabriel is right; the typecast is useless.

Before the statement, you have an uninitialized pointer to an int, i. After the statement is executed, i points to the memory location occupied by the variable t. Therefore, you can now manipulate the value of t using i.

t = 5;
i = &t;
*i = 10; // t is now 10.
cout << t << endl;

Pointers are very important in C and C++ programming. If you have any further questions just reply to this message.

[kuphryn]

One important concept about pointers is that they point to memory addresses, not the actual values.

Kuphryn

[Bob Davis]

Now that I am rereading my post, I feel I should make a distinction. Pointers are very important in plain "C" programming, and less so in C++ programming using libraries like the STL. Standard classes like std::string and std::vector eliminate many cases where pointers would be necessary, letting the classes do all the work for you. Sometimes you can't avoid it and need the extra control that a pointer will give you, and oftentimes, a certain API function will require the use of pointers. While there are often techniques to interface these with STL classes and containers, knowledge of how pointers work is an important part of a C or C++ education, and for other languages (such as assembly) as well.