Question

• Write a C function  f such that …
  • the one parameter of function  f is  p , which is an  int * to the last  int in a contiguous block of random  int values
    • Assume that there are at least 2 int values in the block of int values.
  • function  f returns the penultimate (next-to-last)  int value within the block of int values
    • You must calculate the difference between a pointer and an integer, and apply the dereferencing operator to that difference to determine that value that function  f returns.

Answer 1

Thanks for the question, here is the code for function f, also I write a program to demonstrate it. Please go through the comments so that you can understand and learn.

Hope it helps, let me know for any help with any other questions.

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#include<stdio.h>

int f(int*p){
  
   p = p-1; // subtracting 1 will point to the previous memory address
   return *p; // use deference to get the value at that memory address and return the value
}

int main(){
  
   int arr[] ={1,2,3};
  
   int*p = arr; // this now points to memory address where 1 is stored
   p++; // this now points to memory address where 2 is stored
   p++; // this now points to the lasst element in the array
  
   int penultimate = f(p); // pass the address to the function f
   printf("%d",penultimate); // it should print 2
  
}