I am having trouble with an exercise of finding how many times a number appears in an array and display the value and the count of times it appears in the list. The array can be the size of 100.

Let me be more detailed. I have the program enter a list of numbers all integers and positive. The program then list the numbers in accending order and the number of times that number is in the list. Thanks.

1. put all the numbers in an array and short it.
2. create a 2d array, the first dimension contains the number and the second dimension contains a count of the number of times the number appears. The program will have to iterate through the original array (#1 above) and maintain each array in #2.

c++ <map> will facilitate #2 above, but I'm not familiar enough with it to demonstrate its use.

Well here is what I have so far but the results are not great.
I get repeat info and it prints out -999.
Any ideas?

// Description: Program that reads in a set of positive integers
//              and out puts how many times a number appears in the list.


#include<iostream>
#include<iomanip>
using namespace std;


//function prototypes
void initialize (int numbers[], int listSize);
void readNum (int numbers[], int& listSize);
void selectSort (int numbers[], int listSize);


int main()
{
int Numbers [100];
int count= 0;
int listsize = 100;
int temp;



initialize (Numbers, listsize);


cout <<"Enter a maximum of 100 positive integers ending with -999"<<endl;
readNum (Numbers, listsize);
cout <<endl;
cout <<fixed<<showpoint<<setw(7)<<"Number"<<setw(9)<<"Count"<<endl;


selectSort(Numbers, listsize);


for (int t=0; t< listsize; t++)
{
temp = Numbers[t];
for (int i=0; i < listsize;i++)
{
if (Numbers == temp)
count ++;
}
cout <<setw(5)<<Numbers[t]<<setw(9)<<count<<endl;
count = 0;
}
return 0;
}


void initialize (int numbers[], int listSize)
{
int index;
int Num = 0;
for (index=0; index < 100; index++)
numbers[index] = 0;
}


void readNum (int numbers[], int&listSize)
{
int index =0;
int num =0;
listSize=0;


while (num != -999)
{
cin >>num;
numbers[index] = num;
index++;
listSize++;
}
}


void selectSort (int numbers[], int listSize)
{
int index, minIndex, smallestIndex, temp;


for (index=0; index < listSize - 1;index++)
{
smallestIndex = index;
for (minIndex = index + 1; minIndex < listSize; minIndex++)
if (numbers[minIndex] < numbers[smallestIndex])
smallestIndex = minIndex;


temp = numbers[smallestIndex];
numbers[smallestIndex] = numbers[index];
numbers[index] = temp;


}
}

Edited 3 Years Ago by happygeek: fixed formatting

Attachments
// Name: James Cabrera

// File: Ex11_Cabrera.cpp 

// Date: 2-9-06

// Description: Program that reads in a set of positive integers 
//				and out puts how many times a number appears in the list.

#include<iostream>
#include<iomanip>
using namespace std;

	//function prototypes
void initialize (int numbers[], int listSize);
void readNum (int numbers[], int& listSize);
void selectSort (int numbers[], int listSize);

int main()
{
	int Numbers [100];
	int count= 0;
	int listsize = 100;
	int temp;
	

	initialize (Numbers, listsize);

	cout <<"Enter a maximum of 100 positive integers ending with -999"<<endl;
	readNum (Numbers, listsize);
	cout <<endl;
	cout <<fixed<<showpoint<<setw(7)<<"Number"<<setw(9)<<"Count"<<endl;

	selectSort(Numbers, listsize);

	for (int t=0; t< listsize; t++)
	{
		temp = Numbers[t];
		for (int i=0; i < listsize;i++)
		{
			if (Numbers[i] == temp)
				count ++;
		}
		cout <<setw(5)<<Numbers[t]<<setw(9)<<count<<endl;
		count = 0;
	}
	return 0;
}

void initialize (int numbers[], int listSize)
{
	int index;
	int Num = 0;
	for (index=0; index < 100; index++)
		numbers[index] = 0;
}

void readNum (int numbers[], int&listSize)
{
	int index =0;
	int num =0;
	listSize=0;

	while (num != -999)
	{
		cin >>num;
		numbers[index] = num;
		index++;
		listSize++;
	}
}

void selectSort (int numbers[], int listSize)
{
	int index, minIndex, smallestIndex, temp;

	for (index=0; index < listSize - 1;index++)
	{
		smallestIndex = index;
		for (minIndex = index + 1; minIndex < listSize; minIndex++)
			if (numbers[minIndex] < numbers[smallestIndex])
				smallestIndex = minIndex;
			
			temp = numbers[smallestIndex];
			numbers[smallestIndex] = numbers[index];
			numbers[index] = temp;
			
	}
}

suggestion: read the 100 numbers from a file instead of entering them from the keyboard.

#include<iostream>
#include<iomanip>
using namespace std;

	//function prototypes
void initialize (int numbers[], int listSize);
void readNum (int numbers[], int& listSize);
void selectSort (int numbers[], int listSize);

int main()
{
	int Numbers [100];
	int count= 0;
	int listsize = 100;
	int temp;
	

	initialize (Numbers, listsize);

	cout <<"Enter a maximum of 100 positive integers ending with -999"<<endl;
	readNum (Numbers, listsize);
	cout <<endl;
	cout <<fixed<<showpoint<<setw(7)<<"Number"<<setw(9)<<"Count"<<endl;

	selectSort(Numbers, listsize);

        temp = Numbers[0];
        count = 1;
	for (int t=1; t< listsize; t++)
	{
               if(Numbers[t] == temp)
                  count++;
              else
              {
                   cout << "temp = " << temp << " total = " << count;
                  temp = Numbers[t];
                   count = 1;
              }
	}
        // display count of final number
        cout << "temp = " << temp << " total = " << count;

	return 0;
}

void initialize (int numbers[], int listSize)
{
	int index;
	int Num = 0;
	for (index=0; index < 100; index++)
use listSize in above loop
		numbers[index] = 0;
}

void readNum (int numbers[], int&listSize)
{
	int index =0;
	int num =0;
	listSize=0;
You don't need variable index.  use listSize instead
	while (num != -999)
	{
		cin >>num;
		numbers[index] = num;
		index++;
		listSize++;
	}
}

void selectSort (int numbers[], int listSize)
{
	int index, minIndex, smallestIndex, temp;

	for (index=0; index < listSize - 1;index++)
	{
		smallestIndex = index;
		for (minIndex = index + 1; minIndex < listSize; minIndex++)
			if (numbers[minIndex] < numbers[smallestIndex])
				smallestIndex = minIndex;
			
			temp = numbers[smallestIndex];
			numbers[smallestIndex] = numbers[index];
			numbers[index] = temp;
			
	}
}

You have to decrement listSize if you don't want it to print -999. eg

cout <<"Enter a maximum of 100 positive integers ending with -999"<<endl;
	readNum (Numbers, listsize);
             [b]listSize--;[/b]
	cout <<endl;
	cout <<fixed<<showpoint<<setw(7)<<"Number"<<setw(9)<<"Count"<<endl;

I get repeat info

Show the output.

suggestion: read the 100 numbers from a file instead of entering them from the keyboard.

Or store the numbers in a file and use your OS's redirection capabilities:

C:\>count_numbers <numbers.txt

Thanks guys. Your ideas worked.


You have to decrement listSize if you don't want it to print -999. eg

cout <<"Enter a maximum of 100 positive integers ending with -999"<<endl;
	readNum (Numbers, listsize);
             [b]listSize--;[/b]
	cout <<endl;
	cout <<fixed<<showpoint<<setw(7)<<"Number"<<setw(9)<<"Count"<<endl;

Show the output.

Or store the numbers in a file and use your OS's redirection capabilities:

C:\>count_numbers <numbers.txt
This question has already been answered. Start a new discussion instead.