I call this indented code.

Code:

#include <stdio.h>
#include <stdlib.h>
#define N 9 /* MAIN */
void revArray(int arr[])
{
int temp[N];
int i;
for (i = 0; i < N; ++i) {
temp[i] = arr[N - 1 - i];
}
for (i = 0; i < N; ++i) {
arr[i] = temp[i];
}
}
int *revElement(int arr[])
{
static int idx = N;
idx = --idx;
return arr + idx;
}
void evenOdd(int odd[])
{
int i;
int evenTemp[N / 2];
int oddTemp[(N - 1) / 2];
char tempOdd;
for (i = 0; i < N - 1; i++) {
if (odd[i] % 2 == 0) /* if even integer */
evenTemp[i] = odd[i]; /*store even numbers temporary */
else
oddTemp[i] = odd[i]; /*store odd numbers temporary */
}
for (i = 0; i < (N / 2); ++i) {
odd[i] = evenTemp[i]; /*swap even numbers first in the array */
odd[i - N] = oddTemp[i]; /*swap odd numbers last in the array */
}
}
int main(int argc, char **argv)
{
int a[N];
int idx;
int *p = a;
while (p < a + N)
*p++ = a + N - p;
printf("Original: ");
p = a;
while (p < a + N)
printf("%2d ", *p++); /* Part A: Reverse the array */
revArray(a);
printf("\nReversed: ");
p = a;
while (p < a + N)
printf("%2d ", *p++);
printf("\n"); /* Part B: Return elements in reverse order */
printf("Original: ");
for (idx = 0; idx < N; idx++) {
printf("%2d ", *revElement(a));
}
printf("\n"); /* Part C: Put even numbers first, odd numbers last in the array. Order of
the elements is not important as long as all evens are before first odd */
printf("Even: ");
evenOdd(a);
p = a;
while (p < a + N)
printf("%2d ", *p++);
printf("\n");
system("pause");
}

Original: 9 8 7 6 5 4 3 2 1

Reversed: 1 2 3 4 5 6 7 8 9

Original: 9 8 7 6 5 4 3 2 1

Even: 2 4 6 8 5 3 7 9 1

What is the order of the odd numbers at the end of the array? It seems entirely random to me.

Code:

//!! you're assuming an equal balance of even and odd numbers.
//!! what if the input array was all even numbers?
int evenTemp[N / 2];
int oddTemp[(N - 1) / 2];
for (i = 0; i < N - 1; i++) {
if (odd[i] % 2 == 0) /* if even integer */
//!! you need separate subscripts for each array.
//!! at the moment, you make two copies of the input array (which overflow both local arrays)
evenTemp[i] = odd[i]; /*store even numbers temporary */
else
oddTemp[i] = odd[i]; /*store odd numbers temporary */
}