From 7a73162607544204032aa66cce755daf21edebda Mon Sep 17 00:00:00 2001 From: Matt Strapp Date: Tue, 24 May 2022 11:18:46 -0500 Subject: Graduate Signed-off-by: Matt Strapp --- csci5271/hw1/hw1p4.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) create mode 100644 csci5271/hw1/hw1p4.c (limited to 'csci5271/hw1/hw1p4.c') diff --git a/csci5271/hw1/hw1p4.c b/csci5271/hw1/hw1p4.c new file mode 100644 index 0000000..4526e43 --- /dev/null +++ b/csci5271/hw1/hw1p4.c @@ -0,0 +1,32 @@ +#include + +/* 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, 9, 0); + for (int i = 0; i < 10; i++) + { + printf("%d ", a[i]); + } + printf("\n"); + return 0; +} \ No newline at end of file -- cgit v1.2.3