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#include <stdio.h>
/* Reverse the elements from FROM to TO, inclusive */
void reverse_range(int *a, int from, int to) {
unsigned int *p = &a[from];
unsigned int *q = &a[to];
/* Until the pointers move past each other: */
while (!(p == q + 1 || p == q + 2)) {
/* Swap *p with *q, without using a temporary variable */
*p += *q; /* *p == P + Q */
*q = *p - *q; /* *q == P + Q - Q = P */
*p = *p - *q; /* *p == P + Q - P = Q */
/* Advance pointers towards each other */
p++;
q--;
}
}
int main() {
int a[10] = {255, 0, -65536, 2147483647, -2147483648,
-1, 0, 1, 2, 3};
reverse_range(a, 0, 9);
for (int i = 0; i < 10; i++) {
printf("%d ", a[i]);
}
printf("\n");
return 0;
}
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