P09ex Loading, Sorting, and Searching Arrays an Example |
 |
P09ex Loading, Sorting, and Searching Arrays an Example |
|
P09ex.txt:
50 40 100 30 10 20
Sample Output:
Opening File...
Loading up to 20 whole numbers.
Closing File...
P09ex Juan Marquez
Enter the letter of the desired menu option.
Press the Enter key after entering the letter.
A: List Numbers as Loaded
B: List Numbers Ascending Order
C: List Numbers Descending Order
D: Search Number List
X: Exit the Number Module
Choice: A
Values as read:
position = 1 index = 0 value = 50
position = 2 index = 1 value = 40
position = 3 index = 2 value = 100
position = 4 index = 3 value = 30
position = 5 index = 4 value = 10
position = 6 index = 5 value = 20
Procedure completed. Press Enter to continue:
Choice: B
Values sorted ascending:
position = 1 index = 0 value = 10
position = 2 index = 1 value = 20
position = 3 index = 2 value = 30
position = 4 index = 3 value = 40
position = 5 index = 4 value = 50
position = 6 index = 5 value = 100
Procedure completed. Press Enter to continue:
Choice: c
Values sorted descending:
position = 1 index = 0 value = 100
position = 2 index = 1 value = 50
position = 3 index = 2 value = 40
position = 4 index = 3 value = 30
position = 5 index = 4 value = 20
position = 6 index = 5 value = 10
Procedure completed. Press Enter to continue:
Choice: d
Enter a number to search for: 40
40 is stored in array position 4 and is
referenced with an index value of 3.
Procedure completed. Press Enter to continue:
Choice: d
Enter a number to search for: 25
Early exit...25 is not on the list.
Procedure completed. Press Enter to continue:
Choice: x
Now exiting Number Module...please wait.
Press any key to continue
Source Code:
//P09ex - Array and File Processing - Juan Marquez
//
//Loads, sorts and searches a partially filled array of integers
#include <iostream> // cout and cin
#include <fstream> // file processing
#include <cctype> // tolower
#include <iomanip> // setw
#include <stdlib.h> // system()
using namespace std;
//Declare global variables
//Normally variables that change values are declared locally,
//but here the array and supporting variables are declared globally
//to simplified the function definitions.
const int DECLARED_SIZE = 20;
int numberArray[DECLARED_SIZE], numbersEntered;
void loadArray( );
void sortArrayAscending( );
void sortArrayDescending( );
void displayArray( );
void searchArray( );
void displayContinuePrompt( );
void bubbleSort( );
//bubbleSort included as an informational item.
void main( )
{
char choice;
//loadArray with numbers from the data file
loadArray( );
//check to see what the user wants to do
do // while (choice != 'X')
{
cout << "P09ex Juan Marquez \n\n";
cout << "Enter the letter of the desired menu option. \n"
<< "Press the Enter key after entering the letter. \n \n"
<< " A: List Numbers as Loaded \n"
<< " B: List Numbers Ascending Order \n"
<< " C: List Numbers Descending Order \n"
<< " D: Search Number List \n"
<< " X: Exit the Number Module \n \n"
<< "Choice: ";
cin >> choice;
choice = toupper(choice);
switch (choice)
{
case 'A':
cout << "\nValues as read:\n";
displayArray( );
displayContinuePrompt( );
break;
case 'B':
cout << "\nValues sorted ascending:\n";
sortArrayAscending( );
displayArray( );
displayContinuePrompt( );
break;
case 'C':
cout << "\nValues sorted descending:\n";
sortArrayDescending( );
displayArray( );
displayContinuePrompt( );
break;
case 'D':
searchArray( );
displayContinuePrompt( );
break;
case 'X':
cout << "\nNow exiting Number Module...please wait.\n\n";
break;
default:
cout << "\a \n\n Invalid Option Entered - Please try again. \n\n";
} // end of switch
} while (choice != 'X');
return;
}//end of main
void loadArray( )
{
cout << "Opening File...\n";
//Open the file for input;
ifstream inFile;
inFile.open("P09ex.txt");
//If there are any errors, display an error message and return.
if (inFile.fail())
{
cout << endl << endl
<< "Error: Input file NOT found. " << endl << endl;
numbersEntered = 0;
return;
}
cout << "Loading up to " << DECLARED_SIZE << " whole numbers.\n";
//initialize index to zero for first array element
int i = 0;
//read the first number
inFile >> numberArray[i];
//Only loads up to 20 numbers.
//Additional data in the file is ignored.
while (! inFile.eof())
{
i++;
if (i < DECLARED_SIZE)
inFile >> numberArray[i];
else
break; //get out of the loop
}
numbersEntered = i;
cout << "Closing File...\n\n";
inFile.close();
return;
}
void sortArrayAscending( )
{
int minIndex, minValue, holdValue;
for (int i = 0; i < (numbersEntered - 1); i++) //walk through array
{ //outer loop keeps track
minIndex = i; //of where the next value
minValue = numberArray[i]; //should be placed.
for (int i2 = i + 1; i2 < numbersEntered; i2++)
{ //inner loop finds the
if (numberArray[i2] < minValue) //lowest value to move
{
minIndex = i2; //save the new low number
minValue = numberArray[i2]; //found
}
}
holdValue = numberArray[i]; //swap the values
numberArray[i] = numberArray[minIndex];
numberArray[minIndex] = holdValue;
}
return;
}
void sortArrayDescending( )
{
//For a descending sort we still walk through the array, but this
//time we are searching for the highest values.
int maxIndex, maxValue, holdValue;
for (int i = 0; i < (numbersEntered - 1); i++) //walk through array
{ //outer loop keeps track
maxIndex = i; //of where the next value
maxValue = numberArray[i]; //should be placed.
for (int i2 = i + 1; i2 < numbersEntered; i2++)
{ //inner loop finds the
if (numberArray[i2] > maxValue) //highest value to move
{
maxIndex = i2; //save the new high number
maxValue = numberArray[i2]; //found
}
}
holdValue = numberArray[i]; //swap the values
numberArray[i] = numberArray[maxIndex];
numberArray[maxIndex] = holdValue;
}
return;
}
void displayArray( )
{
cout << endl;
cout.setf(ios::right); //already on by default for numbers
for (int i = 0; i < numbersEntered; i++)
{
cout << "position =";
cout << setw(3) << (i + 1);
cout << " index =";
cout << setw(3) << i;
cout << " value =";
cout << setw(4) << numberArray[i]
<< endl;
}
return;
}
//Early exit - an early exit from a search can occur when we know that
//the value we are looking for will not be found in the array. To
//implement an early exit, the array most be sorted ascending.
//If we can determine that a value will not be found, we should
//not search the remainder of the array.
void searchArray( )
{
//array must be sorted ascending for early exit logic to work
sortArrayAscending( );
int searchNumber;
bool numberFound = false;
cout << "\nEnter a number to search for: ";
cin >> searchNumber;
for(int i=0; i < numbersEntered; i++)
{
if (searchNumber == numberArray[i]) //check if the value entered is
{ //= to the current array element
numberFound = true;
cout << endl
<< searchNumber << " is stored in array position "
<< i + 1
<< " and is \nreferenced with an index value of "
<< i << ". \n\n";
break; //get out of for-loop
}
else if (searchNumber < numberArray[i]) //Early exit
{
cout << endl << "Early exit...";
break; //get out of for-loop
}
}
if (false == numberFound)
cout << searchNumber << " is not on the list.\n";
return;
}
void displayContinuePrompt( )
{
char prompt;
cout << "\nProcedure completed. Press Enter to continue: ";
cin.ignore();
prompt = cin.get( );
system("cls"); //clear the screen
return;
}
//presented as informational item
void bubbleSort( )
{
int holdValue;
for (int i = 0; i < (numbersEntered - 1); i++) //Number of entries in array.
{
for (int i2 = 0; i2 < numbersEntered - 1; i2++)//Inner loop finds the
{ //lowest value to move.
if (numberArray[i2] > numberArray[i2 + 1]) //Low values float up.
{
holdValue = numberArray[i2]; //swap the values
numberArray[i2] = numberArray[i2 + 1];
numberArray[i2 + 1] = holdValue;
}
}
}
return;
}
// end of program