Negative number outputs that should be positive

Question

I am working on a java project and I have a loop that drives me crazy.

The program accepts input, N, which is a positive integer. I want my loop to do the following:

Let's say that N = 10. The cycle will take all numbers from 1 to 10, raise it to the fifth power and store each value in an array of length N.

It works (apparently) correctly up to N = 73 , I think. As soon as N reaches 74 or higher, he randomly gives me negative numbers for 74 ^ ​​5. Which is clearly wrong. The larger the number, the more negatives it gives me.

 private static int _theLimit = EquationSolver.getLimit(); //input "N" private static int length = (int) (_theLimit); //length of possible solutions array = N static int[] _solutions = new int[length]; public static void solutionRun() { for(int i = 1; i <=_theLimit ;) { //theLimit refers to the input N; for numbers from 1 until N for (int p = 0; p <= _solutions.length-1; p++) { //solutions is an array that stores all possible solutions to ^5 from 1 to N; _solutions[p] = i*i*i*i*i; //p refers to the array location, increments with each new i i++; } } for(int q = 0; q<=_solutions.length-1; q++){ //outputs solutions for debugging purposes System.out.println(_solutions[q]); } } 

Answer 1

The problem is that you just passed a range that allows an integer.

Int allow numbers from -2,147,483,648 to the maximum value of 2,147,483,647 (inclusive) ( source ), since 74^5 = 2,219,006,624 . Thus, more than Int can handle.

If you want to use a wider range, you can use the java BigInteger Class. Code example:

 BigInteger pow(BigInteger base, BigInteger exponent) { BigInteger result = BigInteger.ONE; while (exponent.signum() > 0) { if (exponent.testBit(0)) result = result.multiply(base); base = base.multiply(base); exponent = exponent.shiftRight(1); } return result; } 

Considerations: This may not be very effective and may not work for negative reasons or indicators. Use it as an example of how to use BigIntegers.

Instead of BigInteger, you can also use the long type, which ranges from 9,223,372,036,854,775,808 to 9,223,372,036,854,775,807 (inclusive) ( source ).

Do not use double for this purpose, as you may have problems.

Answer 2

I do not work in Java, but hope this helps!

Try the following command: public static final int MAX_VALUE to see the maximum value that int can be in your current environment. The default value is 2147483647 (this will be 2 ^ 31 - 1). 74 ^ 5 = 2073071593, which works, but 75 ^ 5 = 2219006624, which is too high. Use BigInteger to support your range of numbers.