Error in displaying the largest and smallest number

Question

I was attempting to write a program for exercise 2.19 in How to Program, but I ran into some difficulties.

The program is supposed to have the user enter three integers and then display the sum, average, and product of those integers.

The only problem I am having is with displaying the largest and smallest. When I ran the program and entered three integers (8, 9, and 10), the output read Smallest is 8 AND Smallest is 9.

I was hoping you could tell me why.

#include <iostream>
using namespace std;

int main ()
{   int x, y, z, sum, ave, prod;

    cout << "Input three different integers ";
    cin >> x >> y >> z;

    sum = x + y + z;
    cout << "\nThe sum is " << sum;

    ave = (x + y + z) / 3;
    cout << "\nThe average is " << ave;

    prod = x * y * z;
    cout << "\nThe product is " << prod;

    if (x < y, x < z)
      {cout << "\nSmallest is " << x;}

    if (y < x, y < z)
      {cout << "\nSmallest is " << y;}

    if (z < x, z < y)
      {cout << "\nSmallest is " << z;}

    if (x > y, x > z)
      {cout << "\nLargest is " << x << endl;}

    if (y > x, y > z)
      {cout << "\nLargest is " << y << endl;}

    if (z > x, z > y)
      {cout << "\nLargest is " << z << endl;}

    return 0;
}

P.S. I am doing this to study, this is not homework.

Answer 1

You need to rewrite this if condition

if (x < y, x < z)

to be

if (x < y && x < z)

and do the same for all of the remaining if conditions you have.

Edit: All experssions seperated by comma will be evaluated so if you have something like that x = 5, y = 6; it will evaluate both of them and set x to 5 and y to 6 but z = (x=5, y=6); this will cause z to be set to 6 just like y as y=6 was the last term in the list of comma separated terms.

Answer 2

int main() {

  std::cout << "Enter three numbers: ";

  int sum = 0;
  double avg = 0.;
  int product = 0;
  int smallest = std::numeric_limits<int>::max();
  int largest = std::numeric_limits<int>::min(); // the initializers here might not be correct, but the gist is in place...

  for (int i = 0; i < 3; ++i) {
    int val = 0;
    std::cin >> val;

    sum += val;
    avg += val;
    product *= val;

    if (val < smallest) smallest = val;
    if (val > largest) largest = val;
  }
  avg /= 3.; // This can also be done in the for loop, I just forget how.

  std::cout << "Sum: " << sum;
  // etc...  The calculations are all done.
}

Answer 3

Replace your commas, with && for an AND operator, meaning both of the conditions have to be true, or || which is an OR operator, if you want any or both conditions to be satisfied.

from C++ docs:

The comma operator (,) is used to separate two or more expressions that are included    
where only one expression is expected. When the set of expressions has to be evaluated 
for a value, only the rightmost expression is considered.

Answer 4

Instead of comma, you want && i.e.

if (x < y , x < z)
  {cout << "\nSmallest is " << x;}

should be

if (x < y && x < z)
  {cout << "\nSmallest is " << x;}

Answer 5

Use && in place of , inside your if conditions.

Answer 6

By now you realize that && is for AND and that you should use this operator instead of the comma, ,. But did you know you can also use they keyword and in place of its symbol equivalent?:

if ( x < y and x < z ) {

}