Posts Tagged java example
Example of Generic class with two type parameters.
class TwoGen<T,V>
{T ob1;
V ob2;
TwoGen(T o1, V o2)
{ ob1=o1;
ob2=o2;
}
void showTypes()
{System.out.println("Type of T is "+ ob1.getClass().getName());
System.out.println("Type of V is "+ ob2.getClass().getName());
}
T getob1()
{ return ob1;
}
V getob2()
{return ob2;
}
}
class GenDemo2
{public static void main(String a[])
{TwoGen<Integer,String> tgobj= new twoGen<Integer,String>(88,"Generics");
tgobj.showTypes();
int t=tgobj.getob1();
System.out.println("value of t: "+t);
String str =tgobj.getob2();
System.out.println("value of str: "+ str);
}
}
A simple Generics example.
class GenDemo
{ public static void main(String a[])
{ // Create a Gen reference for integers
Gen<Integer> iob;
iob.showType();
int v=iob.getob();
System.out.println("value: "+v);
Gen<String> strob = newGen<String>("Generics Test");
strob.showType();
String str= strob.getob();
System.out.println("value: "+ str);
}
}
class Gen<T>
{T ob;
Gen(T o)
{ob=o;
}
T getob()
{return ob;
}
void showType()
{System.out.println("Type of T is " +ob.getClass().getName());
}
}
Scanner to read various types of data from a file.
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();
}
}
Scanner to read double numbers from a file and display their average.
It uses scanner to read double numbers from a file and display their average. It is assumed that input is terminated by the string “done”.
import java.util.*;
import java.io.*;
class AvgFile{
public static void main(String a[]) throws IOException{
int count =0;
double sum=0;
//Write output to a file.
FileWriter fout= new FileWriter ("test.txt");
fout.write("2 3.4 5 6 7.4 9.1 10.5 done");
fout.close();
FileReader fin= new FileReader ("Test.txt");
Scanner src = new Scanner (fin);
//Read and sum numbers
while(src.hasNext()) {
if(src.hasNextDouble()) {
sum+= src.nextDouble();
count++;
}
else {
String str =src.next();
if(str.equals("done")) break;
else {
System.out.println("ERROR");
return;
}
}
}
fin.close();
System.out.println("Average is " +sum/ count);
}
}
-
FeedCount
Recent Comments