Week 07 Tutorial Questions

  • How is everyone going with the assignment? Are you enjoying it?

    Where can you go to get help?

  • Write a function that takes in a 2D array of ints and multiplies every value in the array by a given int.

    It will have this prototype:

    void scalar_multiply(int rows, int columns, int matrix[rows][columns],  int scalar);

  • What is a pointer? How can you declare and initialise a pointer?

  • What will happen when each of the following statements is executed (in order)?

    int n = 42;
int *p, *q;
p = &n;
*p = 5;
*q = 17;
q = p;
*q = 8;

    Filling out the follwing table may be helpful:

    Address int n = 42; int *p;
    int *q;    		 p = &n; *p = 5; *q = 17; q = p; *q = 8;
    0xFF80
    0xFF84
    0xFF88
    0xFF8C
    0xFF90
    Note: Address lengths have been reduced for brevity.

  • What does the char *word input mean? What's the relationship between an array and a pointer?

  • What is a struct? What are the differences between structs and arrays?

  • This C code:

    int x;
int a[6];

x = 10;
a[3 * 2] = 2 * 3 * 7;
printf("%d\n", x);

    mysteriously printed 42. How could this happen when x is clearly assigned only the value 10?

    How does the output change if we create a another int after the array?

    How can you easily detect such errors before they have mysterious effects?