How do I reverse an array?

Question

Write the definition of a function reverse , whose first parameter  is an array  of integers  and whose second parameter  is the number of elements  in the array . The function reverses the elements  of the array . The function does not return a value .

I believe the beginning would look like this:

void reverse(int array[ ], int size)
{
int i;
for(i=0; i//Not sure what to do now
}

Answer 1

If the goal is to reverse that array in-place, then you really want to stop at size/2 instead of size in that for loop.



Inside the loop, using a int temporary variable, swap the contents of array[i] with array[size-1-i]:



int temp = array[i];

array[i] = array[size-1-i]

array[size-1-i] = temp;



If you run that with i ranging from 0 to size-1, then you will reverse the array twice, leaving it in the original order. Not good.



for (i=0; i
for (i=size/2 - 1; i>=0; --i) .... this works too



The second version avoids computing and storing size/2 for comparison. Older, unoptimized compilers would compute size/2 on every iteration of the loop.



Also, you might occasionally see (size>>1) instead of size/2. Shifts are faster than division, and C/C++ compilers can't optimize signed integer division by 2 into shifts because of the bonehead rounding modes that ISO/ANSI chose.



For now, just use the first version, and be aware that the others exist. You probably won't have to worry about this sort of micro-optimization, ever.

Answer 2

1

Answer 3

If you are size is ''N'' ,then you have to start the ''for'' loop from the ''N'' to the ''0''...then print the array..now it in the reverse order...

The code looks like this ::



for(i=n;i>0;i++)

{

printf('' %d '',array[i]),

}



Thank you.array of integers with three elements such that

a[0] = 1

a[1] = 2

a[2] = 3

Then on reversing the array will be

a[0] = 3

a[1] = 2

a[0] = 1

Answer 4

Refer this

http://www.programmingsimplified.com/c-program-reverse-array

Answer 5

Why not start from the end?

int i;

for(i=size-1; i >=0; i--)

Wait..did you mean in same array?



int temp;

for(int i = 0; i < array.length/2; i++)

{

temp = array[i];

array[i] = array[array.length - i - 1];

array[array.length - i - 1] = temp;

}



for (int i = 0; i < array.length; i++)

System.out.println("array " +a[i]);

Answer 6

just change expression in for()



for (i=size-1; i>=0; i--)

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