Objective-C Programming: The Big Nerd Ranch Guide

Getting the data at an address

If you have an address, you can get the data stored there using the * operator. Have the log display the value of the integer stored at addressofI.

int main(int argc, const char * argv[])
{
    int i = 17;
    int *addressOfI = &i;
    printf("i stores its value at %p\n", addressOfI);
    printf("this function starts at %p\n", main);
    printf("the int stored at addressOfI is %d\n", *addressOfI);
    return 0;
}

Notice that the asterisk is used two different ways in this example:

• When you declared addressOfI to be an int *. That is, you told the compiler “It will hold an address where an int can be stored.”

• When you read the int value that is stored at the address stored in addressOfI. (Pointers are also called references. ...