To Convert A Number Into Words

import java.io.*;
public class NumberNames
{
static String A[]={"","One","Two","Three","Four","Five","Six","Seven","Eight","Nine","Ten","Eleven","Twelve","Thirteen","Fourteen","Fifteen","Sixteen","Seventeen","Eighteen","Nineteen"};
static String B[]={"","","Twenty","Thirty","Forty","Fifty","Sixty","Seventy","Eighty","Ninety"};
static String ConvertToName(int number, int divisionR, int divisionC)
{
if(number==0)return "";
String div[][]={{"","thousand","lakh","crore","arab","hundred arab"},{"","thousand","million","billion","trillion","quadrillion"}};
String s;
if(number< 20) return removeXtraSpc(A[number]+" "+div[divisionR][divisionC]+" "); s=Integer.toString(number); while(s.length()< 3) s="0"+s; int x=s.charAt(2)-48; int y=s.charAt(1)-48; int z=s.charAt(0)-48; if(y> 1) s=B[y]+" "+A[x]+" ";
else s=A[10*y+x]+" ";
if(z!=0)
s=A[z]+" Hundred "+((x!=0||y!=0)?" And ":"")+s;
return removeXtraSpc(s+" "+div[divisionR][divisionC]);
}

public static String removeXtraSpc(String s)
{
int a=0;
while(a< s.length()-1) { if(s.charAt(a)==s.charAt(a+1)&&s.charAt(a)==' ') { String S1=s.substring(0,a); String S2=s.substring(a+1,s.length()); s=S1+S2; continue; } a++; } return s; } public static void main(String aa[])throws IOException { BufferedReader br=new BufferedReader(new InputStreamReader(System.in)); String s=null; int x=0; do{ try{ System.out.println("Enter a valid Positive Integer: "); s=br.readLine(); if(s.length()>18) continue;
x=Integer.parseInt(s);
}catch(Exception e)
{
s=null;
}
}while(s==null||x< 0); if(x==0) s="Zero"; else if(x< 1000) s=ConvertToName(x,0,0); else { char c='.'; do{ System.out.println("Enter a choice: "); System.out.println("1: For Name in Indian System"); System.out.println("2: For Name in International System"); s=br.readLine(); if(s.length()!=1) continue; c=s.charAt(0); }while(c< '1'||c> '2');
s=Integer.toString(x);
c=(char)(c-49);
int a=(c==0?2:3);
int b=1;
String S=s.substring(s.length()-3,s.length());
String t=ConvertToName(Integer.parseInt(S),0,0);
if(Integer.parseInt(S)< 100) t=" and "+t; c=(char)(s.length()-3); while(c-a> 0)
{
S=s.substring(c-a,c);
t=ConvertToName(Integer.parseInt(S),a-2,b++)+" "+t;
c=(char)(c-a);
}
if(c-a<=0)
{
S=s.substring(0,c);

t=ConvertToName(Integer.parseInt(S),a-2,b++)+" "+t;
}
s=t;
}//else closes here
s=removeXtraSpc(s);
System.out.println(s);
}//main() closes here
}//class closes here

Shortest Function to find if a number is prime

class prime
{
public static boolean PrimeCheck(int a)//a should be greater than 0
{
for(int i=2; i<=a/2; i++)
if(a%i==0)
return false;
return true;
}
}

java program To find all the sets of consecutive natural numbers which add up to give the given number

import java.io.*;
class combi
{
private static int N;
private static int sum;

public static void main(String args[])throws IOException
{
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
String S;
System.out.print("Enter an integer: ");
S=br.readLine();
int i=Integer.parseInt(S);
combi A= new combi(i, 0);
A.calc();
}

public combi(int a, int b)
{
N=a;
sum=b;
}


public void calc()throws IOException
{
for(int i=1; i<=N/2;i++)
{
for(int j=i; j<=(N+1)/2; j++)
{
sum+=j;
if(sum==N)
{
for(int a=i; a<=j; a++)
{
System.out.print(a);
System.out.print(a }
System.out.println("");
System.out.println("");
sum=0;
break;
}
}
sum=0;
}

}
}

java program To find whether two strings are anagrams

import java.io.*;
class anagrams
{
public void main(String args[])throws IOException
{
String s1,s2;
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
System.out.println("Anagram Tester! Enter the strings:");
System.out.print("String 1: ");
s1=br.readLine();
System.out.print("String 2: ");
s2=br.readLine();
s1=removewhitespace(s1);
s2=removewhitespace(s2);
s1=s1.toLowerCase();
s2=s2.toLowerCase();

if(s1.length()!=s2.length())System.out.print("Not anagrams(no. of letters not same)!");
else
{
for(int i=0;i {
for(int j=0;j {
if(s1.charAt(i)==s2.charAt(j)){s2=delete(s2,j);break;}
}
}
if(s2.equals("")) System.out.print("The strings are anagrams!");
else System.out.print("Not anagrams "+s2);
}
}

public String removewhitespace(String s)
{
for(int i=0;i {
if(s.charAt(i)==' ')s=delete(s,i);
}
return s;
}

public String delete(String s,int ind)
{
String str=s.substring(ind+1,s.length());
s=s.substring(0,ind);
s=s+str;
return s;
}
}

java program on Amicable numbers

class amicable

{

public static void main(String args[])

{

for(int i=2; i<=1000; i++)

{

for(int j=i+1; j<=1000; j++)

{

if(facSum(i)==j&&facSum(j)==i)

{ System.out.println(i+" and "+j+" are Amicable!");

}

}

}

}

public static int facSum(int a)

{

int c=0;

for(int s=1; s<=a/2; s++)

{

if(a%s==0)

c+=s;

}

return c;

}

}