Question
Write a program that reads in a list of integers into an array with base type int. Provide the facility to either read this array from the keyboard or
from a file, at the user’s option. If the user chooses file input, the program should request a file name. You may assume that there are fewer than 50 entries in the array. Your program determines how many entries there are.
The output is to be a two-column list. The first column is a list of the distinct array elements; the second column is the count of the number of
occurrences of each element. The list should be sorted on entries in the
first column, largest to smallest.
CHAPTER 7 / Arrays
For example, for the input
-12 3 -12 4 1 1 -12 1 -1 1 2 3 4 2 3 -12
the output should be
N Count
4 2
3 3
2 2
1 4
-1 1
-12 4
Answer
#include <iostream>
#include <string>
#include <fstream>
using namespace std;
void readFromKeyboard(int [], int&);
void readFromFile(int [], int&);
void Sort(int [], int);
void printValues(const int [], int);
void printOccurrenceResult(const int [], int);
int main()
{
const int MAX_INTEGERS = 50;
int integersArray[MAX_INTEGERS];
int entries;
int numberOfEntries;
int userChoice;
cout << "Enter the number of entries: ";
cin >> entries;
while(entries < 0 || entries >= 50)
{
cout << "Enter the number of entries fewer than 50: ";
cin >> entries;
}
numberOfEntries = entries;
cout << "\n1. Read Integers from the keyboard" << endl;
cout << "2. Read Integers from a file" << endl;
cout << "Enter your choice: ";
cin >> userChoice;
while(userChoice != 1 && userChoice != 2)
{
cout << "Enter choice (1 or 2 only): ";
cin >> userChoice;
}
if(userChoice == 1)
readFromKeyboard(integersArray, entries);
else
readFromFile(integersArray, entries);
printValues(integersArray, entries);
Sort(integersArray, entries);
printValues(integersArray, entries);
printOccurrenceResult(integersArray, entries);
system("pause");
return 0;
}
void readFromFile(int integers[], int &n)
{
string inFileName;
ifstream inFile;
cout << "\nEnter a file name: ";
cin >> inFileName;
inFile.open(inFileName);
while(inFile.fail())
{
cout << inFileName << " file is not opened or found." << endl;
cout << "Enter a current file name: ";
cin >> inFileName;
inFile.open(inFileName);
}
int i = 0;
while(inFile >> integers[i] && i < n)
{
i++;
}
if(i == 0)
{
cout << "The file contains no numbers that is the file is empty." << endl;
system("pause");
exit(1);
}
else if(i != n)
{
cout << "The file contains less than " << n << " numbers." << endl;
n = i;
}
}
void Sort(int integers[], int n)
{
for(int i = 0; i < n - 1; i++)
{
for(int j = i; j < n; j++)
{
if(integers[i] < integers[j])
{
int temp = integers[i];
integers[i] = integers[j];
integers[j] = temp;
}
}
}
}
void printValues(const int integers[], int n)
{
cout << "\nThe integers stored in the array:" << endl;
for(int i = 0; i < n; i++)
cout << integers[i] << " ";
cout << endl;
}