C++ help with arrays..

Cro · 10-14-2005, 08:58 PM

hi guys. im really having probs with arrays. Basically i open an input file like:

Code:

ifstream infile;

infile.open("A:\\students.txt");

now the file contains different int numbers...like:

76,89,150,135,200,76,12,100,150,28,178,189,167,200,175,150,87,99,129,149,176,200,87,35,157,189

now what i need to do is to put all those in an array...and then determine the number of students having scroes in each of the following ranges:

0-24, 25-49, 50-74, 75-99, 100-124, 125-149, 150-174, and 175-200.

it should then display the results like:

------------COUNTS(the total number)
0-24 ------- 1
25-49-------- 2
50-74 --------0
.. ----------- .
. ----------- .
.. ----------- .
.

please if someone could help me.... thanks!

ive tried some code, but im really stuck:,, this is what ive done:

Code:

int list[26];
	int z;
	
	infile >> list[26];
	while(infile)
	{
		///for(z = 0; z < 26; z++)
		//{
			
			if(list[z] > 0 && list[z] < 25)
			{
				list[z]++;
				sum = sum + list[z];
				
				
			}
		infile >> list[26];
		cout << sum;
	}

Cwwoods · 10-15-2005, 10:30 PM

Have you tried something like this?

Example of Binary Seach.....

int binarysearch (int array[], int size, int searchKey)

{

int low = 0, middle, high;

high = -1;

while (low <= high);

{

middle = (low + high) / 2;

if (searchKey == array [middle])
return middle;

else if (searchKey < array [middle])
high = middle -1;

else
low = middle + 1;

}

return -1; //not found

}

Does this help? Once it finds the values in the array you should be able to sort them with some more code.

**mgoldb2** · 10-16-2005, 04:33 AM

PHP Code:


			
#include <iostream> 

#include <fstream> 

#include <iomanip>



using namespace std; 



int main() 

{ 

    int n[26];

    

    ifstream input;  

    input.open("input.dat"); 

    

    if(input.fail( ))

    { 

       cout << "Cannot open file"<<endl; 

       return 1; 

    } 



    int x=0;

    

    while(!input.eof())

    {

        input>> n[x];

        x++;

    }



    input.close( );

    

    int y=25;

    int size=0;

    cout<<setw(3)<<"Range"<<setw(9)<<"count"<<endl<<endl;

    for(int a=0;a<8;a++)

    {

        int z=0;

        while(z<x)

        {

            if(n[z]<y && n[z]>y-25)

            {

                size++;

            }

            

            z++;

            

        }

        

        cout<<setw(3)<<y-25<<setw(2)<<"-"<<setw(3)<<y<<setw(3)<<size<<endl;

        size=0;

        y=y+25;

    }

    

            

    return 0;

}

This will work. basically what it does it save each value in the file into a array. then it searchers the array 8 times each time looking for a different one of the ranges you needed then displays how many time it found a number in that range.

Cro · 11-05-2005, 06:27 PM

thanks for all the help :) very much appreciated!

10-14-2005, 08:58 PM	#1 (permalink)
Cro Registered User Join Date: Oct 2005 Posts: 5 OS: XP	C++ help with arrays.. hi guys. im really having probs with arrays. Basically i open an input file like: Code: ifstream infile; infile.open("A:\\students.txt"); now the file contains different int numbers...like: 76,89,150,135,200,76,12,100,150,28,178,189,167,200,175,150,87,99,129,149,176,200,87,35,157,189 now what i need to do is to put all those in an array...and then determine the number of students having scroes in each of the following ranges: 0-24, 25-49, 50-74, 75-99, 100-124, 125-149, 150-174, and 175-200. it should then display the results like: ------------COUNTS(the total number) 0-24 ------- 1 25-49-------- 2 50-74 --------0 .. ----------- . . ----------- . .. ----------- . . please if someone could help me.... thanks! ive tried some code, but im really stuck:,, this is what ive done: Code: int list[26]; int z; infile >> list[26]; while(infile) { ///for(z = 0; z < 26; z++) //{ if(list[z] > 0 && list[z] < 25) { list[z]++; sum = sum + list[z]; } infile >> list[26]; cout << sum; }

10-15-2005, 10:30 PM	#2 (permalink)
Cwwoods Registered User Join Date: Oct 2005 Posts: 4 OS: XP Prof	Binary Search or Bubble Sort? Have you tried something like this? Example of Binary Seach..... int binarysearch (int array[], int size, int searchKey) { int low = 0, middle, high; high = -1; while (low <= high); { middle = (low + high) / 2; if (searchKey == array [middle]) return middle; else if (searchKey < array [middle]) high = middle -1; else low = middle + 1; } return -1; //not found } Does this help? Once it finds the values in the array you should be able to sort them with some more code.

10-16-2005, 04:33 AM	#3 (permalink)
mgoldb2 TSF Enthusiast Join Date: Dec 2004 Posts: 604 OS: windows xp	PHP Code: #include <iostream> #include <fstream> #include <iomanip> using namespace std; int main() { int n[26]; ifstream input; input.open("input.dat"); if(input.fail( )) { cout << "Cannot open file"<<endl; return 1; } int x=0; while(!input.eof()) { input>> n[x]; x++; } input.close( ); int y=25; int size=0; cout<<setw(3)<<"Range"<<setw(9)<<"count"<<endl<<endl; for(int a=0;a<8;a++) { int z=0; while(z<x) { if(n[z]<y && n[z]>y-25) { size++; } z++; } cout<<setw(3)<<y-25<<setw(2)<<"-"<<setw(3)<<y<<setw(3)<<size<<endl; size=0; y=y+25; } return 0; } This will work. basically what it does it save each value in the file into a array. then it searchers the array 8 times each time looking for a different one of the ranges you needed then displays how many time it found a number in that range. __________________

11-05-2005, 06:27 PM	#4 (permalink)
Cro Registered User Join Date: Oct 2005 Posts: 5 OS: XP	thanks for all the help :) very much appreciated!