In short: strcmp compares null-terminated C strings strncmp compares at most N characters of null-terminated C strings memcmp compares binary byte buffers of N bytes So, if you have these strings: const char s1[] = “atoms\0\0\0\0”; // extra null bytes at end const char s2[] = “atoms\0abc”; // embedded null byte const char s3[] = … Read more
Yes, this declaration is bad practice, because it allows many ways of accidentally provoking Undefined Behavior by writing to a string literal, including: cool[0] = ‘k’; strcpy(cool, “oops”); On the other hand, this is perfectly fine, since it allocates a non-const array of chars: char cool[] = “cool”;
If I stick a ‘\0’ into the middle of the allocated memory, does (a.) free() still work properly, and Yes. (b.) does the space after the ‘\0’ become inconsequential? Once ‘\0’ is added, does the memory just get returned, or is it sitting there hogging space until free() is called? Depends. Often, when you allocate … Read more
Is it possible to print out only the last 5 bytes of this string? Yes, just pass a pointer to the fifth-to-the-last character. You can determine this by string + strlen(string) – 5. What about the first 5 bytes only? Use a precision specifier: %.5s #include <stdio.h> #include <string.h> char* string = “Hello, how are … Read more
According to CodeGuru: CString to std::string: CString cs(“Hello”); std::string s((LPCTSTR)cs); BUT: std::string cannot always construct from a LPCTSTR. i.e. the code will fail for UNICODE builds. As std::string can construct only from LPSTR / LPCSTR, a programmer who uses VC++ 7.x or better can utilize conversion classes such as CT2CA as an intermediary. CString cs … Read more
See the C FAQ, Question 1.32 Q: What is the difference between these initializations? char a[] = “string literal”; char *p = “string literal”; My program crashes if I try to assign a new value to p[i]. A: A string literal (the formal term for a double-quoted string in C source) can be used in … Read more