how to use fstream library

**salmanriaz** · 03-11-2009

have an assignment to read 10000 files from a file name"10000ia" and then after applying selection sort on it it should be print on another file say"10000sorted".what i have done i include fstream library

Code:

ifstream ifile;

ifile.open("10000ia.txt",ios::in);

ifile.seekg(0);

ifile>>;

ifile.close();

ofstream file;

file.open("10000.txt",ios::out);

file<<selection(a);

file.close();

system("pause");

return 0;

}


int selection(int a[10000])
{
    int i,excount=0,comcount=0;

int min;

for( int i=0;i<10000;i++)
{
     min=i;
     
     for (int j=i+1;j<10000;j++)
     
     {
         if (a[min]>a[j])
         {
               min=j;
                        
         }   
     
     }
         
             int temp=a[i];
                 a[i]=a[min];
                 a[min]=temp;
                 comcount=(15*(15+1))/2;
                 excount=excount+1;
         
                  
       
     

}


                          

cout<<"Number of exchange are:"<<excount<<"\n";
cout<<"Number of comparisons are:"<<comcount<<"\n";

return 0;
}

**salmanriaz** · 03-11-2009

i dont know that what to write in file>>????

**QuantumPete** · 03-11-2009

This should go to the C++ forum

But basically the idea is
stream >> buffer
So you'll need some sort of buffer to direct the file information into

QuantumPete

**laserlight** · 03-11-2009

Moved to C++ Programming forum.

**salmanriaz** · 03-12-2009

how could i set the 10000 numbers into an array how i code it that all numbers
sets in an array for example a[1..10000]=all numbers in file named"10000ia.txt"...

**laserlight** · 03-12-2009

Originally Posted by salmanriaz

how could i set the 10000 numbers into an array how i code it that all numbers
sets in an array for example a[1..10000]=all numbers in file named"10000ia.txt"...

Just a moment...

Firstly, do you know how to read a single number from the file into a variable? Then, can you be sure that there will be no more than 10000 numbers to read in, or is there a variable number of numbers such that a fixed upper bound is inappropriate?

**salmanriaz** · 03-12-2009

as far as i know if i assign a particular number to a variable for example:
int x=1 then i can easily read it(x) from using fstream function (ifstream) but if there are only numbers given in the list then how could i read them as they r not assigning to any variable.
as far as ur question about the numbers then yes there are constant 10000 numbers in the list..

**laserlight** · 03-12-2009

Originally Posted by salmanriaz

as far as i know if i assign a particular number to a variable for example:
int x=1 then i can easily read it(x) from using fstream function (ifstream) but if there are only numbers given in the list then how could i read them as they r not assigning to any variable.

Sorry, but I do not understand what you are saying. Maybe this will help: write a program to read in an integer from standard input, then print the integer read to standard output. Show us your code for this program, then we will show you how to transform it to read an integer from a file.

Originally Posted by salmanriaz

as far as ur question about the numbers then yes there are constant 10000 numbers in the list..

In that case an array will be good enough, but if you know how to use a std::vector<int>, then you could still use that.

Thread: how to use fstream library

Thread Tools

Search Thread

Display

how to use fstream library

Similar Threads

What's an import library?

Property Set Library (PSL) - Announcement

Makefile for a library

very weird .h problem

ARGH! fstream errors