CODEWITHSUNDEEP
java
Ahmed Ramadan
Ahmed Ramadan

Reputation: 35

How to calculate big numbers in java?

ex I want the sum form 1^1 to n^n : 1^1 + 2^2 + 3^3 + .............+n^n and I know how, but the problem that I want only the last ten numbers of the sum but I have only to use primitive data. how can I calculate large numbers using only primitive data.

public static void main(String args[]) {
    Scanner in = new Scanner(System.in);
    short n = in.nextShort();
    if(n < 0) {
        System.out.println("please give a positive number");
        return;
    }
    long l  = rechnung(n);
    System.out.println(l);
    String str = Objects.toString(l, null);
    String s = ziffer(str);
    System.out.println(s);
}

public static long rechnung(short j) {
    long summe = 0;
    for(int i = 1; i <= j; i++) {
        summe += Math.pow(i,i);
    }
    return summe;
}

public static String ziffer(String s) {
    String str = "";
    int k =s.length() - 10;
    int cond = k + 9;
    if(s.length() <= 10) {
        return s;
    }
    for(int j = k; j <= cond; j++) {
        str = str + s.charAt(j);
    }
    return str;
}

Upvotes: 1

Views: 213

Answers (1)

Peter Lawrey
Peter Lawrey

Reputation: 533492

As you only need to keep the lower 10 digits you can use a % 10_000_000_000L to keep the digits you need with each calculation.

Upvotes: 2

Related Questions