C/C++ How to swap the first and last elements of a vector using a function in C++?

[Teh]

What i am doing work because i can only get 40 30 30 40 as output?

Write a function SwapVectorEnds() that swaps the first and last elements of its vector parameter. Ex: sortVector = {10, 20, 30, 40} becomes {40, 20, 30, 10}. The vector's size may differ from 4.

#include <iostream>
#include <vector>
using namespace std;

/* Your solution goes here  */void SwapVectorEnds(vector<int>& sectorVector){ 
int i = 0;
for ( i = 0; i < sectorVector.size() - 1; ++i) {
  sectorVector.at(i) = sectorVector.at(sectorVector.size() - 1 - i);
}
   return;
}
   
   
   
   
   
int main() {
   vector<int> sortVector(4);
   int i = 0;

   sortVector.at(0) = 10;
   sortVector.at(1) = 20;
   sortVector.at(2) = 30;
   sortVector.at(3) = 40;

   SwapVectorEnds(sortVector);

   for (i = 0; i < sortVector.size(); ++i) {
      cout << sortVector.at(i) << " ";
   }
   cout << endl;

   return 0;
}

Testing with original sortVector = {10, 20, 30, 40}



Expected output:
40 20 30 10



Your output:
40 30 30 40

 

[MarkFL]

You are looping over the entire vector, which isn't necessary. What I would do is first store the last element in a variable, put the first element's value into the last element, and then put the value of the variable we stored the last element's initial value into the first element. :)