CODEWITHSUNDEEP
java
Bharat Gaikwad
Bharat Gaikwad

Reputation: 530

NumberFormatException, BigInteger in java

Getting following run-time error 

C:\jdk1.6.0_07\bin>java euler/BigConCheck
Exception in thread "main" java.lang.NumberFormatException: For input string: "z
"
        at java.lang.NumberFormatException.forInputString(NumberFormatException.
java:48)
        at java.lang.Integer.parseInt(Integer.java:447)
        at java.math.BigInteger.<init>(BigInteger.java:314)
        at java.math.BigInteger.<init>(BigInteger.java:447)
        at euler.BigConCheck.conCheck(BigConCheck.java:25)
        at euler.BigConCheck.main(BigConCheck.java:71)

My Code

package euler;
import java.math.BigInteger;
class BigConCheck
{

public int[] conCheck(BigInteger big)
{
    int i=0,q=0,w=0,e=0,r=0,t=0,mul=1;
    int a[]= new int[1000];
    int b[]= new int[7];
    BigInteger rem[]= new BigInteger[4]; 
    BigInteger num[]= new BigInteger[4]; 
    for(i=0;i<4;i++)  
    num[i]=big;   // intialised num[1 to 4][0] with big
    String s="1",g="0";
    for(i=0;i<999;i++)
    s = s.concat(g);
    BigInteger divi[]= new BigInteger[4]; 

    for(i=0;i<5;i++)  
    {
        divi[i]=new BigInteger(s);  
        int z = (int)Math.pow((double)10,(double)i);

        BigInteger zz = new BigInteger("z");    // intialised div[1 to 4][0] with big
        divi[i]=divi[i].divide(zz);
    }

    for(i=0;i<996;i++)   // 5 consecative  numbers.
    {
        for(int k=0;k<5;k++)
        {
            rem[k] = num[k].mod(divi[k]);
            b[k]=rem[k].intValue();
            mul= mul*b[k]; 
            /*int z = (int)Math.pow((double)10,(double)(k+1));
        String zz = "z"; 
        BigInteger zzz = new BigInteger(zz);
        num[k]=num[k].divide(zzz);   */
        }

        a[i]=mul;
        for(int p=0;p<5;p++)
        {
            BigInteger qq = new BigInteger("10");
            num[p]=num[p].divide(qq);
        }       
    } 
    return a;
} 

public int bigestEleA(int u[])
{
    int big=0;
    for(int i=0;i<u.length;i++)
    if(big<u[i])
    big=u[i];

    return big;
}


public static void main(String args[])
{
    int con5[]= new int[1000]; 
    int punCon;
    BigInteger bigest = new BigInteger("7316717653133062491922511967442657474235534919493496983520312774506326239578318016984801869478851843858615607891129494954595017379583319528532088055111254069874715852386305071569329096329522744304355766896648950445244523161731856403098711121722383113622298934233803081353362766142828064444866452387493035890729629049156044077239071381051585930796086670172427121883998797908792274921901699720888093776657273330010533678812202354218097512545405947522435258490771167055601360483958644670632441572215539753697817977846174064955149290862569321978468622482839722413756570560574902614079729686524145351004748216637048440319989000889524345065854122758866688116427171479924442928230863465674813919123162824586178664583591245665294765456828489128831426076900422421902267105562632111110937054421750694165896040807198403850962455444362981230987879927244284909188845801561660979191338754992005240636899125607176060588611646710940507754100225698315520005593572972571636269561882670428252483600823257530420752963450");


    BigConCheck bcc = new BigConCheck();
    con5=bcc.conCheck(bigest);
    punCon=bcc.bigestEleA(con5);
    System.out.println(punCon);


}

}

please point out whats goes wrong @ runtime and why

thanks in advance...

Upvotes: 3

Views: 25853

Answers (7)

Delark
Delark

Reputation: 1323

For those interested in generating longs with characters without hashing, it is possible to transform characters to long via BigInteger simply by using the constructor with a radix: BigInteger(String value, int radix)

There is a catch thought, the int which defines the log base, must scale not with the length of the String, but instead with the number of characters that make out the collection of characters that will be used in the creation of the String.

As far as I'm aware, for an alpha numeric collection, the int is 36 (26 + 10), this may be wrong thought.

There is also a limitation, I believe there are symbols that simply cannot be parsed, like "-" or " " or "_" (I've tried adding to the int base radix and nothing) which means the String must be transformed before parsing and it cannot be returned back to String after it being parsed via BigInteger.

Why is it useful?? I don't know haha, I have use it to autogenerate id's from Strings ,instead of using hashes, I remember somhwere this is kinda better than hashcode since a hash from String does not ensure uniqueness, an also this method as opposed to base Encoding gives extricity a long value, which may be useful for many api's that require a long id.

Upvotes: 0

Kris
Kris

Reputation: 1

A common mistake is writing new BigInteger("",num) instead of new BigInteger(""+num)

Upvotes: 0

fmucar
fmucar

Reputation: 14558

BigInteger zz = new BigInteger("z");

you are passing non-numerical string thats the reason.

EDIT:

It takes string but it expects the string to be a numerical value. "z" does not have any numerical meaning.

Upvotes: 3

Buhake Sindi
Buhake Sindi

Reputation: 89209

BigInteger Javadoc states for BigInteger(String value)

Translates the decimal String representation of a BigInteger into a BigInteger. The String representation consists of an optional minus sign followed by a sequence of one or more decimal digits. The character-to-digit mapping is provided by Character.digit. The String may not contain any extraneous characters (whitespace, for example).

So your code:

BigInteger zz = new BigInteger("z");    // intialised div[1 to 4][0] with big

is totally incorrect, but this is correct:

BigInteger zz = new BigInteger("5566");

EDIT: Based on your comment, this would be simpler by using the String.valueOf() method:

int z = (int)Math.pow((double)10,(double)i);
BigInteger zz = new BigInteger(String.valueOf(z));

Upvotes: 3

Paŭlo Ebermann
Paŭlo Ebermann

Reputation: 74800

Could it be that you want this instead?

    int z = (int)Math.pow((double)10,(double)i);

    BigInteger zz = new BigInteger(z);

Note the missing quotes here. (Of course, this will only work for i < 10.)

Upvotes: 1

nicholas.hauschild
nicholas.hauschild

Reputation: 42834

This is the line causing you grief:

BigInteger zz = new BigInteger("z");    // intialised div[1 to 4][0] with big

While BigInteger does work with String's, those String's must be parsable into numbers.

EDIT** Try this:

 Integer z = (Integer)Math.pow((double)10,(double)i);

 BigInteger zz = new BigInteger(z.toString());

Upvotes: 5

Bozho
Bozho

Reputation: 597402

new BigInteger("z"); is not meaningful. You can only pass numbers in constructor.

This is pretty obvious, so the next time you get an exception go the the exact line in your code shown in the exception stacktrace and you will most likely spot the problem.

Upvotes: 3

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