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In the second strcat_nc() call, the compiler will happily compile the code with no warnings, but the resulting code will attempt to modify the "str1" literal, which may be impossible; the literal may not be defined in the heap. This violates STR05-A. Use pointers to const when referencing referring to string literals.
In the final strcat_nc() call, the compiler generates a warning about ateempting to cast away const on str4. This is a valid warning.
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