I need to output the smallest number that is entered. I can't seem to figure out how to do it though.

small.cpp

``````#include <iostream>
#include <algorithm>
#include "arrayListType.h"

using namespace std;

int main()
{
arrayListType<int> intList(100);
// int min(int first, int last);
int counter;
int number;

cout<<  "Enter 5 integers: ";

for (counter = 0; counter < 5; counter++) // Use of for loop to enter intListinsertat
{
cin >> number;
intList.insertAt(counter, number);
}

cout << endl;
cout << "The list you entered is: ";
intList.print();

cout << "The smallest number  is: ";
intList.print();
cout << endl;

}
``````

arrayListType.h

``````#ifndef H_arrayListType
#define H_arrayListType

#include <iostream>
#include <cassert>

using namespace std;

template <class elemType>
class arrayListType
{
public:
const arrayListType<elemType>& operator=
(const arrayListType<elemType>&);
bool isEmpty() const;
//Function to determine whether the list is empty
//Postcondition: Returns true if the list is empty;
//    otherwise, returns false.
bool isFull() const;
//Function to determine whether the list is full.
//Postcondition: Returns true if the list is full;
//    otherwise, returns false.
int listSize() const;
//Function to determine the number of elements in the list
//Postcondition: Returns the value of length.
int maxListSize() const;
//Function to determine the size of the list.
//Postcondition: Returns the value of maxSize.
void print() const;
//Function to output the elements of the list
//Postcondition: Elements of the list are output on the
//   standard output device.
bool isItemAtEqual(int location, const elemType& item) const;
//Function to determine whether the item is the same
//as the item in the list at the position specified by
//Postcondition: Returns true if the list[location]
//    is the same as the item; otherwise,
//               returns false.
void insertAt(int location, const elemType& insertItem);
//Function to insert an item in the list at the
//position specified by location. The item to be inserted
//is passed as a parameter to the function.
//Postcondition: Starting at location, the elements of the
//    list are shifted down, list[location] = insertItem;,
//    and length++;. If the list is full or location is
//    out of range, an appropriate message is displayed.
void insertEnd(const elemType& insertItem);
//Function to insert an item at the end of the list.
//The parameter insertItem specifies the item to be inserted.
//Postcondition: list[length] = insertItem; and length++;
//    If the list is full, an appropriate message is
//    displayed.
void removeAt(int location);
//Function to remove the item from the list at the
//position specified by location
//Postcondition: The list element at list[location] is removed
//    and length is decremented by 1. If location is out of
//    range,an appropriate message is displayed.
void retrieveAt(int location, elemType& retItem) const;
//Function to retrieve the element from the list at the
//position specified by location.
//Postcondition: retItem = list[location]
//    If location is out of range, an appropriate message is
//    displayed.
void replaceAt(int location, const elemType& repItem);
//Function to replace the elements in the list at the
//position specified by location. The item to be replaced
//is specified by the parameter repItem.
//Postcondition: list[location] = repItem
//    If location is out of range, an appropriate message is
//    displayed.
void clearList();
//Function to remove all the elements from the list.
//After this operation, the size of the list is zero.
//Postcondition: length = 0;
int seqSearch(const elemType& item) const;
//Function to search the list for a given item.
//Postcondition: If the item is found, returns the location
//    in the array where the item is found; otherwise,
//    returns -1.
void insert(const elemType& insertItem);
//Function to insert the item specified by the parameter
//insertItem at the end of the list. However, first the
//list is searched to see whether the item to be inserted
//Postcondition: list[length] = insertItem and length++
//     If the item is already in the list or the list
//     is full, an appropriate message is displayed.
void remove(const elemType& removeItem);
//Function to remove an item from the list. The parameter
//removeItem specifies the item to be removed.
//Postcondition: If removeItem is found in the list,
//      it is removed from the list and length is
//      decremented by one.

arrayListType(int size = 100);
//constructor
//Creates an array of the size specified by the
//parameter size. The default array size is 100.
//Postcondition: The list points to the array, length = 0,
//    and maxSize = size

arrayListType(const arrayListType<elemType>& otherList);
//copy constructor

~arrayListType();
//destructor
//Deallocates the memory occupied by the array.

protected:
elemType *list;  //array to hold the list elements
int length;      //to store the length of the list
int maxSize;     //to store the maximum size of the list
};

template <class elemType>
bool arrayListType<elemType>::isEmpty() const
{
return (length == 0);
}

template <class elemType>
bool arrayListType<elemType>::isFull() const
{
return (length == maxSize);
}

template <class elemType>
int arrayListType<elemType>::listSize() const
{
return length;
}

template <class elemType>
int arrayListType<elemType>::maxListSize() const
{
return maxSize;
}

template <class elemType>
void arrayListType<elemType>::print() const
{
for (int i = 0; i < length; i++)
cout << list[i] << " ";

cout << endl;
}

template <class elemType>
bool arrayListType<elemType>::isItemAtEqual
(int location, const elemType& item) const
{
return(list[location] == item);
}

template <class elemType>
void arrayListType<elemType>::insertAt
(int location, const elemType& insertItem)
{
if (location < 0 || location >= maxSize)
cerr << "The position of the item to be inserted "
<< "is out of range" << endl;
else
if (length >= maxSize)  //list is full
cerr << "Cannot insert in a full list" << endl;
else
{
for (int i = length; i > location; i--)
list[i] = list[i - 1];   //move the elements down

list[location] = insertItem;  //insert the item at the
//specified position

length++;     //increment the length
}
} //end insertAt

template <class elemType>
void arrayListType<elemType>::insertEnd(const elemType& insertItem)
{

if (length >= maxSize)  //the list is full
cerr << "Cannot insert in a full list" << endl;
else
{
list[length] = insertItem;   //insert the item at the end
length++;   //increment the length
}
} //end insertEnd

template <class elemType>
void arrayListType<elemType>::removeAt(int location)
{
if (location < 0 || location >= length)
cerr << "The location of the item to be removed "
<< "is out of range" << endl;
else
{
list[location] = list[length - 1];

length--;
}
} //end removeAt

template <class elemType>
void arrayListType<elemType>::retrieveAt
(int location, elemType& retItem) const
{
if (location < 0 || location >= length)
cerr << "The location of the item to be retrieved is "
<< "out of range." << endl;
else
retItem = list[location];
} //end retrieveAt

template <class elemType>
void arrayListType<elemType>::replaceAt
(int location, const elemType& repItem)
{
if (location < 0 || location >= length)
cerr << "The location of the item to be replaced is "
<< "out of range." << endl;
else
list[location] = repItem;

} //end replaceAt

template <class elemType>
void arrayListType<elemType>::clearList()
{
length = 0;
} //end clearList

template <class elemType>
int arrayListType<elemType>::seqSearch(const elemType& item) const
{
int loc;
bool found = false;

for (loc = 0; loc < length; loc++)
if (list[loc] == item)
{
found = true;
break;
}

if (found)
return loc;
else
return -1;
} //end seqSearch

template <class elemType>
void arrayListType<elemType>::insert(const elemType& insertItem)
{
int loc;

if (length == 0)   //list is empty
list[length++] = insertItem;    //insert the item and
//increment the length
else if (length == maxSize)
cerr << "Cannot insert in a full list." << endl;
else
{
loc = seqSearch(insertItem);

if (loc == -1)    //the item to be inserted
//does not exist in the list
list[length++] = insertItem;
else
cerr << "the item to be inserted is already in "
<< "the list. No duplicates are allowed." << endl;
}
} //end insert

template<class elemType>
void arrayListType<elemType>::remove(const elemType& removeItem)
{
int loc;

if (length == 0)
cerr << "Cannot delete from an empty list." << endl;
else
{
loc = seqSearch(removeItem);

if (loc != -1)
removeAt(loc);
else
cout << "The item to be deleted is not in the list."
<< endl;
}
} //end remove

template <class elemType>
arrayListType<elemType>::arrayListType(int size)
{
if (size < 0)
{
cerr << "The array size must be positive. Creating "
<< "an array of size 100. " << endl;

maxSize = 100;
}
else
maxSize = size;

length = 0;

list = new elemType[maxSize];
assert(list != NULL);
}

template <class elemType>
arrayListType<elemType>::~arrayListType()
{
delete [] list;
}

template <class elemType>
arrayListType<elemType>::arrayListType
(const arrayListType<elemType>& otherList)
{
maxSize = otherList.maxSize;
length = otherList.length;
list = new elemType[maxSize]; //create the array
assert(list != NULL);         //terminate if unable to allocate
//memory space

for (int j = 0; j < length; j++)  //copy otherList
list [j] = otherList.list[j];
} //end copy constructor

template <class elemType>
const arrayListType<elemType>& arrayListType<elemType>::operator=
(const arrayListType<elemType>& otherList)
{
if (this != &otherList)   //avoid self-assignment
{
delete [] list;
maxSize = otherList.maxSize;
length = otherList.length;

list = new elemType[maxSize];  //create the array
assert(list != NULL);   //if unable to allocate memory
//space, terminate the program
for (int i = 0; i < length; i++)
list[i] = otherList.list[i];
}

return *this;
}

#endif
``````

## All 11 Replies

Compare each element entered by the user to the previous input. If the number is smaller then set it to min. Otherwise keep the min you already have. Since you don't know what min should be on the first entry you either need to set min to the first entry and then compare each subsequent iteration or you can set min to be the maximum number possible. You can get the largest possible number for a type by using:

``````int min = std::numeric_limits<int>::max()
``````
commented: Well explained. +15

I tried editing my small.cpp. It outputs a number but only the last number I entered.

``````#include <iostream>
#include <algorithm>
#include "arrayListType.h"

using namespace std;

int main()
{
arrayListType<int> intList(100);

int counter;
int number;

cout<<  "Enter 5 integers: ";

for (counter = 0; counter < 5; counter++) // Use of for loop to enter     intListinsertat
{
cin >> number;
intList.insertAt(counter, number);
}

cout << endl;
cout << "The list you entered is: ";
intList.print();

cout << "The smallest number  is: ";
for ( int i ; i < counter; ++i)

int smallest;
if ( number > smallest )

smallest = number ;

cout << smallest;
cout << endl;

}
``````

didn't you mean to have it as if number is less than the smallest then smallest is changed to number?

How would you do the problem? I'm a little lost to be honest. I'm still a novice.

@phony You need to do the check while you are getting the input from the user. Otherwise you need to iterate through the contents of `intList` and find the smallest element. As an example this this how you would find the smallest value in an array of integers:

``````int data[arraySize] // arraySize is some size for the array
// fill data with values

int min = data; // set min to the first element and then check the rest
// start at 1 since min is already data
for (int i = 1; i < arraySize; i++)
{
if (data[i] < min) // if the element is smaller then min then make min that value.
min = data[i];
// otherwise we do nothing and let the loop continue.
}
``````

I'm going to be honest I'm still a little lost.

What part are you having trouble with?

How my .cpp would look.

``````#include <iostream>
#include <algorithm>
#include "arrayListType.h"

using namespace std;

int main()
{
arrayListType<int> intList(100);

int counter;
int number;

cout << ".\n\n\n"; //Output user information
cout << "" << "\n\n";
cout<<  "Enter 5 integers: ";

for (counter = 0; counter < 5; counter++) // Use of for loop to enter intListinsertat
{
cin >> number;
intList.insertAt(counter, number);

}

cout << endl;
cout << "The list you entered is: ";
intList.print();
int smallest = 0;
intList.retrieveAt(0,smallest);
cout << "The smallest element in the list is:";

for (int i = 0; i < counter; ++i) //works out smallest number

{
intList.retrieveAt(i,number);

if( number<smallest ) //compares smallest value with current element
{
smallest=number;
}
}
cout<<smallest;

cout << endl;

}
``````

I updated my .cpp code. Is there a more efficient way to do it?

Is there?

Doing a linear search through a list or an array to find the minimum is O(N) or linear time. If you were to sort and then grab the first element using either qsort or std::sort that would be O(Nlog2(N)) which is log(N) times more inefficient. The only way to get min or max in a more efficient way than O(N) that I know of is to use a container that sorts itself when elements are entered. Then you either get the fist or last element from the container which is generally O(1) or constant time. check out set for a sorted container. You are paying for that constant time though as the set is sorted with every element that get entered.

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