[CC150] Ch1.2 Reverse C-style string

1.2 Write code to reverse a C-Style String. (C-String means that “abcd” is represented as five characters, including the null character.)

Classic question...
Algorithm is simple, but got stuck during initialization... usages of string.c_str() and "abcd"
return const char*, and then error happens during swap the elements in const array...

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