Pointers and references practice (2019)

pointers and references practice

This page contains set of challenges that you can go through to test your understanding on the topic. It aditionally contains links to resources and or explanations on the topic.

This page was last updated on 10.11.2019

You can find its source on github.

1. Pointer is a variable that can contain a memory address.

   Recommended reading: The C Programming Language", 2nd edition, Kernighan and Ritchie; Chapter 5

   Useful links: cppreference.com , cplusplus.com , Stanford 106 , random pointer tutorial , and more pointers .

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   A reference is a simple reference datatype that is less powerful but safer than the pointer type inherited from C.

   Useful links: cppreference.com , isocpp.org .

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2. 1. Create pointer 'pNum' that points to int 'num'. Set value of num to 10 by deferencing pNum pointer. Initialize new varibale 'num2' by directly acessing 'num' throught pNum pointer. Output num2.

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   2. How would you output memory address of num from previous example? How would you output memory address of num by using pointer? How would you ouput memory address of the pointer itself?

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   3. What does following code output?

   void coutA(int*a){
       cout << &a << " | " << a << " | " << *a << " | in pointer func" << endl;
   }
       
   void coutA(int&a){
       cout << &a << " | " << a << "\t\t | in reference func" << endl;
   }
                       
   int main() {
       int a = 42;
       int *pA = &a;
       int **pA2 = &pA;
   
       coutA(a);
       coutA(&a);
       coutA(pA);
       coutA(*pA);
       coutA(*pA2);
       coutA(**pA2);
   
       cout << endl;
       cout << &a << endl;
       cout << &pA << endl;
       cout << &pA2 << endl;

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   3. Initialize int and float variables 'foo' and 'bar' both to 0. Declare a new void pointer and use it to change values of foo and bar to 3 and 3.4 respectively. Output values of foo and bar.

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   4. Define an array of first 5 natural numbers. Output whole array by deferencing a pointer and change 3 to 4 before outputing it.

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   5. What does following code output?

   int a = 1;
   int b = 2;
   int c = 3;
   int arr[] = {a,b,c};
   
   *(arr+2) = 7;
   
   for(int i = 0; i<sizeof(arr)/sizeof(*arr); ++i){
       std::cout << &arr[i] << " | " << arr[i] << std::endl;
       std::cout << arr + i << " | " << *(arr+i) << std::endl;
   }

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   6. Define new pancake using struct bellow and assign it values 10 and 7.68 using pointers. Output pancake info using alternative notation.

   struct Pancake {
       int i;
       float f;
   };

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© 2019 Tomislav (frainfreeze) Kucar.