Pick a number say 3 so you can enter 3 numbers then substract the maximum from the min

Question

I tried changing a lot of integers and stuff but it didn't work and it gives me a random number like 53289432 even tho lets say i put in 3:5,1,2 it should output 3 since 5-2 is 3.

#include <iostream>

using namespace std;

int main()
{
 int n;
 cin>>n;
 int x[n];
 int mn;
 int mx;

 for(int i=1;i<n;i++)
 {
     cin>>x[i];
     for(int j=1;j<n;j++)
     {
     if(x[i]>x[j]);
     }
 {
    x[i]=mn;
 }
 }
  for(int i=1;i<n;i++)
 {
    
   for(int j=1;j<n;j++)
     {
     if(x[i]<x[j]);
     }
 {
    x[i]=mx;
 }
 }
 cout<<mx-mn;
 
 
 
}

Did you mean to have your `if`s do nothing? And `mn` and `mx` aren't ever initialized. Plus you're using a variable-length array. — Stephen Newell, Mar 21 '22 at 16:16
`int x[n];` is not standard C++. See [Why aren't variable-length arrays part of the C++ standard?](https://stackoverflow.com/questions/1887097/why-arent-variable-length-arrays-part-of-the-c-standard) — Wyck, Mar 21 '22 at 16:18

score 1 · Answer 1 · answered Mar 21 '22 at 16:24

You don't need an array:

int smallest = 0;
int largest  = 0;
std::cout << "Enter quantity: ";
int quantity;
std::cin >> quantity;
if (quantity < 1)
{
  std::cerr << "Invalid quantity.\n";
  return 1;
}
std::cout << "Enter number: ";
std::cin >> smallest;
largest = smallest;
for (int i = 1; i < quantity; ++i)
{
  std::cout << "Enter number: ";
  int number;
  std::cin >> number;
  if (number < smallest) smallest = number;
  if (number > largest)  largest  = number;
}
std::cout << "maximum from minimum: " << (smallest - largest) << "\n";
std::cout << "minimum from maximum: " << (largest - smallest) << "\n";

The above code uses a running minimum/maximum, so no arrays are needed.

No need for variable length arrays or having to figure out the array capacity at compile time.

Nice. Not much left to do except `"substract the maximum from the min" (which seems odd - I'd expect the other way) and cope with overflow potential. — chux - Reinstate Monica, Mar 21 '22 at 16:27

score 0 · Answer 2 · answered Mar 24 '22 at 16:45

Your code carries several holes,

Firstly,

for(int i=1;i<n;i++)
{ 
  cin>>x[i];

This won't take n integers, it will only take (n-1) integers as input. You need to initialise i=0, for n integers;

Secondly,

for(int i=1;i<n;i++)
{
   cin>>x[i];
   for(int j=1;j<n;j++)
   {
     if(x[i]>x[j]); //This will compare with garbage when i=1 and j>1
   }
   {
     x[i]=mn;
   }
}

Your comparison, will only be valid for first iteration of i=1 and j=1, after j>1, it will pick garbage value, since, you haven't taken any input yet.

It is suggested, to first take all the inputs, then do the comparison, or other operations.

Here is my solution

I think this is what you are trying to do!

#include <iostream>
#include <climits>

using namespace std;

int main()
{
  int n;
  cin>>n;
 
  int x[n];
  int mn;
  int mx;
  
  //First take the inputs in array x

  for(int i=0;i<n;i++)
  {
     cin>>x[i];
  }

  //Find maximum and store it in mx

  mx = INT_MIN; //This stores minimum in mx variable (climits)
  for(int j=0;j<n;j++)
  {
     if(mx<x[j])
       mx=x[j];
  }

  //Find minimum and store it in mn

  mn = INT_MAX; //This stores maximum in mn variable (climits)
  for(int j=0;j<n;j++)
  {
     if(mn>x[j])
       mn=x[j];
  }
  int ans = mx - mn;
  cout<<ans<<endl;
 
}

There is a better solution where you don't use extra space(array), and by using only 2 variables, you can find the difference. But I would recommend you to first understand this concept, and take a look, how array works, before moving towards any optimised solution.

Try avoid giving way complete code. The answer is too long to comprehend. — JATothrim, Mar 24 '22 at 17:01
I was just, highlighting his mistakes, so that he could understand better. — , Mar 25 '22 at 06:17

Pick a number say 3 so you can enter 3 numbers then substract the maximum from the min

2 Answers2