C ++中用户定义数组的问题

Question

I am trying to create an array using cin to define the size. While that seems to be working (based on what I currently have), none of the other stuff I want to do seems to be working.

For instance, I want to use a for loop to find the smallest int in the array since I will then need to compare it with all the other ints in the array, but no matter where I have the statement to return the smallest int, it does not do it.

What am I doing wrong?

#include <iostream>

using namespace std;

int main(){


  int userSize;
  cout << "Please define size of array: ";
  cin >> userSize;

  int *duckArray = new int[userSize];

  for (int i = 0; i < userSize; i++) {
    cout << "Please enter a number into the array: ";
    cin >> duckArray[i];
  }

  int smallest = duckArray[0];

  for (int i = 0; i < userSize; i++){
    if (duckArray[i] < smallest){
        smallest = duckArray[i];
        cout << smallest << endl;
    }
  }

  //cout << smallest << endl;

  return 0;
}

Answer 1

Your code is working if you change this:

for (int i = 0; i < userSize; i++){
    if (duckArray[i] < smallest){
        smallest = duckArray[i];
    }
}

cout << smallest << endl;

This will find and print the smallest number entered.

Answer 2

Arrays in C++ must have their size declared to the compiler at runtime. Other people are going to explain how you can buffer memory to simulate a dynamically allocating arrays. You can also have your Array at a given size and as the user adds and removes, you can reject inputs over the current size.

I highly recommend you look into Vectors . Vectors are much like ArrayLists in Java. They are a form of higher level collections that resize themselves as you add more elements to them.