Need help with some questions

Question

What's a method that will take an int array list and will take every even number in the list and insert the same number to the right of the initial number. e.g.: [1,2,3,4] would become [1,2,2,3,4,4]

What's a method that will take an array list and move all the odd numbers to be before the even numbers. e.g.: [1,2,3,4] would become [1,3,2,4]

What's a method that will take an array list and square all the numbers in the list. e.g.:[1,2,3,4] would become [1,4,9,16]

Answer 1

using namespace std;

#include <iostream>

#include <stdlib.h>

#include <string.h>

int CompareInt(const void * rec1, const void * rec2)

{

int * intPtr1 = (int*)rec1;

int * intPtr2 = (int*)rec2;

int iNum1=*intPtr1;

int iNum2=*intPtr2;

return(iNum1-iNum2);

}

int duplicateEvens(int * a, int * aDup, int N)

{

int iIndexPos=0;

for (int iLoop=0; iLoop<N; iLoop++)

{

aDup[iIndexPos++]=a[iLoop];

if ((a[iLoop])%2 == 0)

{

aDup[iIndexPos++]=a[iLoop];

}

}

return(iIndexPos);

}

int oddEvenSort(int * a, int * aResult, int N )

{

int * evens = (int*)malloc(N*sizeof(int));

int * odds = (int*)malloc(N*sizeof(int));

int oddIndex=0;

int evenIndex=0;

for (int iLoop=0; iLoop<N; iLoop++)

{

if (a[iLoop]%2==0)

{

evens[evenIndex++]=a[iLoop];

}

else

{

odds[oddIndex++]=a[iLoop];

}

}

qsort(evens,evenIndex,sizeof(int),CompareInt);

qsort(odds,oddIndex,sizeof(int),CompareInt);

memcpy(aResult,odds,oddIndex*sizeof(int));

memcpy(&aResult[oddIndex],evens,evenIndex*sizeof(int));

free(odds);

free(evens);

}

Squares(int * a, int * aSqr, int N)

{

for (int iLoop=0; iLoop<N; iLoop++)

{

aSqr[iLoop] = a[iLoop]*a[iLoop];

}

}

int main()

{

int a[]={1,2,3,4};

int dupEvens[8];

int OddEvenSort[4];

int aSquares[4];

int iReturn = duplicateEvens(a,dupEvens,4);

cout << "duplicate evens " << endl;

for (int iLoop=0; iLoop<iReturn; iLoop++)

{

cout << dupEvens[iLoop] << endl;

}

cout << "****************************************" << endl;

cout << "odd even sort " << endl;

oddEvenSort(a,OddEvenSort,4);

for (int iLoop=0; iLoop<4; iLoop++)

{

cout << OddEvenSort[iLoop] << endl;

}

cout << "*******************************************" << endl;

cout << " Squares " << endl;

Squares(a,aSquares,4);

for (int iLoop=0; iLoop<4; iLoop++)

{

cout << aSquares[iLoop] << endl;

}

}

/*************************************************************************************************/

#*********** PYTHON ************************************

def dupEven( a):

N = len(a)

results=[]

for i in range(N):

results.append(a[i])

if (a[i]%2==0):

results.append(a[i])

return(results)

#********************************************************************************

def dupOdd( a):

N = len(a)

results=[]

for i in range(N):

results.append(a[i])

if (a[i]%2==1):

results.append(a[i])

return(results)

#***************************************************

def evenOddSort(a):

N = len(a)

odds=[]

evens=[]

for i in range(N):

if a[i]%2==0:

evens.append(a[i])

else:

odds.append(a[i])

odds.sort()

evens.sort()

results=[]

nOdds = len(odds)

for i in range(nOdds):

results.append(odds[i])

nEvens =len(evens)

for i in range(nEvens):

results.append(evens[i])

return results

#**************************************************

def Square(A):

results=[]

N=len(A)

for i in range(N):

results.append(A[i]*A[i])

return results

#******************************************************

A=[1,2,3,4]

results = dupEven(A)

print(results)

results = dupOdd(A)

print(results)

results = evenOddSort(A)

print(results)

results = Square(A)

print(results)

Answer 2

Question: What's a method that will take an int array list and will take every even number in the list and insert the same number to the right of the initial number. e.g.: [1,2,3,4] would become [1,2,2,3,4,4]

Answer: The method needs to loop through the array, checking each value and inserting a duplicate if the value is even. The trick is that the loop index needs to increase by 2 when the value is even, so as to skip to the next value in the array. That means that the loop index incrementing should be done in the body of the loop, not the for loop itself (if you're using a for-loop). Secondly, the length of the list needs to be calculated each time by the for-loop, which should happen if you're using the array's size or length method.

Question: What's a method that will take an array list and move all the odd numbers to be before the even numbers. e.g.: [1,2,3,4] would become [1,3,2,4]

Answer: The method needs to loop through the array, moving the odd numbers to the beginning of the list based on an insert index that increases each time another odd number is found. ["Move" means remove and insert.] Initially the index should be initialized to 0. Don't worry about the case where an odd number is the first element in the list - the algorithm will still work.

Question: What's a method that will take an array list and square all the numbers in the list. e.g.:[1,2,3,4] would become [1,4,9,16]

Answer: The method needs to loop through the array, replacing each number by its square.