Posts Tagged File

Scanner to read various types of data from a file.

Posted by admin in Java on June 3rd, 2010

This example shows how to use scanner to read various type(like integer, double, boolean, string) of data from a file.


import java.util.*;

import java.lang.io.*;

class ScanMixed{

public static void main(String a[]) throws IOException {

int i;

double d;

boolean b;

String str;

//Write output to a file

FileWriter fout = new FileWriter("test.txt");

fout.write("Testing Scanner 10 12.2 one true two false");

fout.close();

FileReader fin= new FileReader("Test.txt");

Scanner src= new scanner(fin);

// Read to end.

while (src.hasNext()) {

if(src.hasNextInt()) {

i= src.nextInt();

System.out.println("int:  "+ i);

}

else if(src.hasNextDouble()) {

d= src.nextDouble ();

System.out.println("double: "+ d);

}

else if(src.hasNextBoolean()) {

b=src.nextBoolean();

System.out.println("boolean: "+b);

}

else {

str =src.next();

System.out.println("String: "+ str);

}

}

fin.close();

}

}

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Program to display complete information about a file: Perm, inode, acl bits.

Posted by admin in perl hacks on June 14th, 2009 

#!/usr/bin/perl

use File::stat;
$pwd = (getpwuid($<))[1];
print "$pwd";
                   system "stty -echo";
                   print "Password: ";
                   chomp($word = );
                   print "\n";
                   system "stty echo";

                   if (crypt($word, $pwd) ne $pwd) {
                       print "Sorry...\n";
                   } else {
                       print "ok\n";
                   }
$ret = index("hello this is a test for index","index");
print $ret;
lc("HeLlO");
$str = "\LHeLlO";
print $str;
$len = length("Hello testing...");
print $len;
$filename = "data.txt";
($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,$atime,$mtime,$ctime,$blksize,$blocks) = stat($filename);
@statinfo = stat($filename);
for $val (@statinfo)
	{
		print "$val\n";
	}
                   $sb = stat($filename);
                   printf "File is %s, size is %s, perm %04o, mtime %s\n",$filename, $sb->size, $sb->mode & 07777,scalar localtime $sb->mtime;
$str = "this is sample test";
$str =~ m/sample/g;
$post = pos $str;
print $post;
print quotemeta("this is sample . testing gg :");
split(/,/,'value1,value2');
print "@_";

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PROGRAM TO GENERATE 30000 RANDOM NUMBERS AND WRITE TO FILE RECORDS.TXT IN SORTED ORDER (USED INORDER TRAVERSAL FOR THIS).

Posted by admin in C++ Examples on June 14th, 2009 

#include<iostream.h>
#include<fstream.h>
#include<stdlib.h>

int total=0;
fstream file;
struct bintree
{
int data;
bintree *left,*right;
};

void inorder(bintree *node)
{
if(node->left!=NULL)
inorder(node->left);
file<<" "<<node->data;
if(node->right!=NULL)
inorder(node->right);
}

void makenode(bintree **garb,int num)
{
(*garb)->data=num;
(*garb)->left=NULL;
(*garb)->right=NULL;
}

void makebintree(bintree *garb,bintree **base)
{
if((*base)==NULL)
{
*base=garb;
total++;
return;
}
else if(garb->data==(*base)->data)
{
return;
}
else if(garb->data<(*base)->data)
makebintree(garb,&((*base)->left));
else
makebintree(garb,&((*base)->right));
}
void dump(bintree **node)
{
if(*node==NULL)
return;
if((*node)->left==NULL&&(*node)->right==NULL)
{
delete(*node);
*node=NULL;
}
else
{
dump(&((*node)->left));
dump(&((*node)->right));
dump(node);
}
}
void main()
{
bintree *garb,*root=NULL;
file.open("records.txt",ios::out);
while(total<30000)
{
garb=new bintree;
makenode(&garb,rand());
makebintree(garb,&root);
}
inorder(root);
dump(&root);
file.close();
}

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PROGRAM TO GENERATE 20000 RANDOM KEYS AND WRITE TO FILE KEYS.TXT

Posted by admin in C++ Examples on June 14th, 2009 

#include<iostream.h>
#include<fstream.h>
#include<stdlib.h>

int total=0;
fstream file;
struct bintree
{
int data;
bintree *left,*right;
};

void makenode(bintree **garb,int num)
{
(*garb)->data=num;
(*garb)->left=NULL;
(*garb)->right=NULL;
}

void makebintree(bintree *garb,bintree **base)
{
if((*base)==NULL)
{
*base=garb;
total++;
file<<garb->data<<" ";
return;
}
else if(garb->data==(*base)->data)
{
return;
}
else if(garb->data<(*base)->data)
makebintree(garb,&((*base)->left));
else
makebintree(garb,&((*base)->right));
}
void dump(bintree **node)
{
if(*node==NULL)
return;
if((*node)->left==NULL&&(*node)->right==NULL)
{
delete(*node);
*node=NULL;
}
else
{
dump(&((*node)->left));
dump(&((*node)->right));
dump(node);
}
}
void main()
{
bintree *garb,*root=NULL;
file.open("keys.txt",ios::out);
while(total<20000)
{
garb=new bintree;
makenode(&garb,rand());
makebintree(garb,&root);
}
dump(&root);
file.close();
}

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