Garbage Output from 'smallest' and 'biggest' functions - c++

Question

I'm trying to use two parallel arrays to find which jar of salsa sold the most and sold the least. I'm trying to output the highest and lowest sales number to later turn into a salsa name to display. However, my two void functions keep producing garbage output and I can't figure out why because I used this same algorithm with another programming question yesterday. Also, does anyone have any suggestions in how I can get my sales numbers to output in a straight vertical line? I tried using 'right' and 'setw(30)' but that didn't help much, thank you for your time.
#include <iostream>
#include <string>
#include <iomanip>
using namespace std;
void smallest(string[], int[]);
void biggest(string[], int[]);
int main()
{
const int size = 5;
string name[size] = { "mild", "medium", "sweet", "hot", "zesty"};
int sales[size];
int total = 0;
for (int i = 0; i < size; i++)
{
cout << "Enter the amount of jars of " << name[i] << " salsa that were sold: ";
cin >> sales[i];
while (sales[i] < 0)
{
cout << "Invalid Input! Enter a positive amount of jars of " << name[i] << " salsa that were sold: ";
cin >> sales[i];
}
}
cout << "Salsa Type Amount Sold\n";
cout << "===============================\n";
for (int i = 0; i < size; i++)
{
cout << name[i] << setw(30) << right << sales[i] << endl;
}
for (int i = 0; i < size; i++)
{
total = total + sales[i];
}
cout << "\nThe total sales of jars is: " << total << endl;
smallest(name, sales);
biggest(name, sales);
}
void smallest(string name[], int sales[])
{
int i;
int lowest;
lowest = sales[0];
for (i = 1; i < 5; i++)
{
if (sales[i] < lowest)
{
lowest = sales[i];
}
}cout << "The lowest selling product is: " << sales[i] << endl;
}
void biggest(string name[], int sales[])
{
int i;
int highest;
highest = sales[0];
for (i = 1; i < 5; i++)
{
if (sales[i] > highest)
{
highest = sales[i];
}
}cout << "The highest selling product is: " << sales[i] << endl;
}

Answer 1

You are not printing out the lowest and highest with these lines of code:
cout << "The lowest selling product is: " << sales[i] << endl;
//...
cout << "The highest selling product is: " << sales[i] << endl;
Instead you are printing the value of sales[5], since i == 5. That is an out-of-bounds access, thus the reason for the garbage value (actually, accessing an element out-of-bounds is undefined behavior).
You should be printing whatever the values are at index lowest and highest, not i:
Example:
cout << "The lowest selling product is: " << name[lowest] << endl;
//...
cout << "The highest selling product is: " << name[highest] << endl;
You could have prevented this error by not declaring the loop index i outside the for loop, and instead declare it within the initialization portion of the for loop syntax:
void smallest(string name[], int sales[])
{
int lowest;
lowest = sales[0];
for (int i = 1; i < 5; i++)
{
if (sales[i] < lowest)
{
lowest = sales[i];
}
}
cout << "The lowest selling product is: " << sales[i] << endl; // <-- Compiler error
}
Doing that would have stopped the sales[i] from compiling, since i would be local to the for loop.
Edit:
To print out the lowest and highest names, you should instead figure out the index of the highest and lowest. Then use the index in the final print statement. The code shown above was not completed, but here is an example:
void smallest(string name[], int sales[])
{
int lowest = sales[0];
int lowestIndex = 0;
for (int i = 1; i < 5; i++)
{
if (sales[i] < lowest)
{
lowest = sales[i];
lowestIndex = i
}
}
cout << "The lowest selling product is: " << name[lowestIndex] << endl;
cout << "The lowest selling price is: " << sales[lowestIndex] << endl;
However, using C++ library functions std::min_element and std::distance, you can get the lowest index with two function calls:
#include <algorithm>
//...
void smallest(string name[], int sales[])
{
// get pointer to smallest element
auto iter = std::min_element(sales, sales + 5);
// get index of where the smallest element is
auto idx = std::distance(sales, iter);
// print out results
cout << "The lowest selling product is: " << name[idx] << endl;
cout << "The lowest price is: " << sales[idx] << endl;
}
For the largest element, use std::max_element instead of std::min_element.

Answer 2

After each of your for-loops, you are printing out the value in the array at index i. But i == 5 after the for-loop terminates, which is one-past the end of the array (note that i++ occurs one more time after the last iteration of the for-loop body is run). This is why you are getting garbage data (and why you might sometimes crash the program!)
In order to print out the lowest and highest values, you should just cout the variables that you've already taken the time to store:
cout << "The lowest selling product is: " << lowest << endl;
...
cout << "The highest selling product is: " << highest << endl;

Answer 3

Your print statement is at wrong place. You are printing value out of the loop where i is 5. You have written in 0 to 4 positions in the sales array. There is nothing at index 5. The below-corrected code should work -
void smallest(string name[], int sales[])
{
int i;
int lowest;
lowest = sales[0];
for (i = 1; i < 5; i++)
{
if (sales[i] < lowest)
{
lowest = sales[i];
}
}
cout << "The lowest selling product is: " << lowest << endl;
}
void biggest(string name[], int sales[])
{
int i;
int highest;
highest = sales[0];
for (i = 1; i < 5; i++)
{
if (sales[i] > highest)
{
highest = sales[i];
}
}
cout << "The highest selling product is: " << highest << endl;
}