Question

Chapter 9 (Pointers) - Review Questions

Find the Error

Each of the following definitions and program segments has errors. Locate as many as you can.

46. int ptr* = nullptr;

47. int x, *ptr = nullptr;

&x = ptr;

48. int x, *ptr = nullptr;

*ptr = &x;

49. int x, *ptr = nullptr;

ptr = &x;

ptr = 100; //Store 100 in x

cout << x << endl;

50. int numbers[] = {10, 20, 30, 40, 50};

cout << “The third element in the array is ”;

cout << *numbers + 3 << endl;

51. int values[20], *iptr = nullptr;

iptr = values;

iptr *= 2;

52. float level;

int fptr = &level;

53. int *iptr = &ivalue;

int ivalue;

54. void doubleVal(int val)

{

*val *= 2;

}

55. int *pint = nullptr;

new pint;

56. int *pint = nullptr;

pint = new int;

if (pint == nullptr)

*pint = 100;

else

cout << “Memory allocation error\n”;

57. int *pint = nullptr;

pint = new int[100]; //Allocate memory

.

.

Code that process the array.

.

.

delete pint; // Free memory

58. int *getNum()

{

int wholeNum;

cout << “Enter a number: “;

cin >> wholeNum;

return &wholeNum;

}

59. const int arr[] = {1, 2, 3};

int *ptr = arr;

60. void doSomething(int * const ptr)

{

int localArray[] = {1, 2, 3};

ptr = localArray;

       }

Answer 1

46)should be int *ptr=nullptr(NULL)

47)

int x, *ptr = nullptr;

&x = ptr;

should be ptr=&x;

48)same as above

ptr=&x

49)should be *ptr=100 (ptr assigns the address *ptr has value)

50)It will print 13

it should be like *(numbers+3) this indicates the element

51)If you are assigning a value it should be *iptr=2

52)You cannot assign address to normal variable it shoud be a pointer int *fptr=&level

53)int ivalue should be declared first after words pointer should be declared

54)The parameter should be int *val

55)should be

pint = new int;

56)if it is a null pointer we cannot allocate value so if and else statements inside them should be vice versa

57)should be pint = new int(100); paranthesis not square brackets

58)should return value not an address (return wholenum)

59)should be const int *ptr = arr;

invalid conversion from const int* to int*

60)we canot assign it to constant value

const int localArray[]={1,2,3]

comment if any doubts