Question when copying two sentences to a string pointer using the C++ strcpy_s function

When combining two strings in the char*pszResult inside the function Add(charpszLeft, char pszRight),

int nLenLeft = strlen(pszLeft);

int nLenRight = strlen(pszRight);

char *pszResult = new char[nLenLeft+nLenRight+1]; after allocating memory like this,

To copy strings to newly allocated memory

strcpy_s(pszResult, nLenLeft + 1, pszLeft);

strcpy_s(pszResult+nLenLeft, nLenRight + 1, pszRight);

I write a function like this, but I don't understand what the first strcpy_s function is about, and I don't understand why the second strcpy_s function contains "pszResult+nLenLeft" I understood that I would copy the memory address of the pszResult by doing the pointer operation as much as nLenLeft, is that right? Or is it a different reason?

strcpy

2022-09-21 19:37

1 Answers

Your question is correct.

If you look at msdn (https://msdn.microsoft.com/ko-kr/library/td1esda9.aspx), you will copy it to the strDestination that the first factor points to.

errno_t strcpy_s(
   char *strDestination,
   size_t numberOfElements,
   const char *strSource 
);

"The strcpy_s function copies the contents in the address of strSource, including the terminating null character, to the location that's specified by strDestination."

2022-09-21 19:37

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