Question

Write a function intLog of type Integer -> Integer that returns the exponent of the largest power of 2 less than its integer argument.

This needs to be a haskell function

Answer 1

#include <bits/stdc++.h>

using namespace std;

// Function to return the lowest power

// of 2 close to given positive number

int powOfPositive(int n)

{

    // Floor function is used to determine

    // the value close to the number

    int pos = floor(log2(n));

    return pow(2, pos);

}

// Function to return the lowest power

// of 2 close to given negative number

int powOfNegative(int n)

{

    // Ceil function is used for negative numbers

    // as -1 > -4. It would be opposite

    // to positive numbers where 1 < 4

    int pos = ceil(log2(n));

    return (-1 * pow(2, pos));

}

// Function to find the highest power of 2

void highestPowerOf2(int n)

{

    // To check if the given number

    // is positive or negative

    if (n > 0) {

        cout << powOfPositive(n);

    }

    else {

        // If the number is negative,

        // then the ceil of the positive number

        // is calculated and

        // negative sign is added

        n = -n;

        cout << powOfNegative(n);

    }

}

// Driver code

int main()

{

    int n;

cin>>n;

    highestPowerOf2(n);

    return 0;

}