(C++)

3.How can you use pointer to print the first element of an array? Give an example.

4.Explain the Program Output listed on page 507, Program9-7 of the text book. How does the pointer notation work with array name?

PAGE 507 PROGRAM 9-7:

 1 // This program uses subscript notation with a pointer variable and 2 // pointer notation with an array name. 3 #include  4 #include  5 using namespace std; 6 7 int main() 8 { 9 const int NUM_COINS = 5; 10 double coins[NUM_COINS] = {0.05, 0.1, 0.25, 0.5, 1.0}; 11 double *doublePtr; // Pointer to a double 12 int count; // Array index 13 14 // Assign the address of the coins array to doublePtr. 15 doublePtr = coins; 16 17 // Display the contents of the coins array. Use subscripts 18 // with the pointer! 19 cout << "Here are the values in the coins array: "; 20 for (count = 0; count < NUM_COINS; count++) 21 cout << doublePtr[count] << " "; 22 23 // Display the contents of the array again, but this time 24 // use pointer notation with the array name! 25 cout << " And here they are again: "; 26 for (count = 0; count < NUM_COINS; count++) 27 cout << *(coins + count) << " "; 28 cout << endl; 29 return 0; 30 } 

Program Output

Here are the values in the coins array: 0.05 0.1 0.25 0.5 1 And here they are again: 0.05 0.1 0.25 0.5 1 

Note on Question 3 and 4 above: It is very critical that you thoroughly understand the use of pointers to access elements of an array. This is a very common use case.

5.When you increment/decrement a pointer, are you changing the address or the element at the address? If it is the address, how does the program now how much to increment or decrement? Hint: Remember the use of sizeof function in earlier chapters.

6.Explain the difference between the following; assuming ptr1 and ptr2 are pointers to integers.

If (ptr1 < ptr2)

If (*ptr1 < *ptr2)

7.

a.Why do we need dynamic memory allocation?

b.What commands are used to allocate and release memory?

c. What is memory leak, and how do you prevent it?