Write C + + program to implement strcpy () function

Read this question on the Internet and write the following procedure:

Code Listing 1:

Char *cpystr (char *des,const char *src)
{
int i = 0;
if (NULL = = des | | NULL = = src)
return NULL;
while (src[i]! = ' + ')
{
Des[i] = Src[i];
i++;
}

Return des;
}

1. This write can implement the replication function, except that C + + syntax has a vulnerability, support const char* to char * default conversion, if the call

Cpystr () writes like this: Cpystr ("Hello", "Hello"), can be compiled through (tested under VS2013). A segment error occurred while running.

To avoid this error, you can define a function as follows:,

Char *cpystr (const char *des,const char *SRC)

｛

printf ("Error:the first arg can ' t be const\n");

Exit (0);

｝

If the knowledge Declaration is Char *cpystr (const char *des,const char *src), and the function is not defined, an error occurs.

"Error LNK2019: unresolved external symbol" char * __cdecl cpystr (char const *,CHAR const *) "([email Protected]@[email protected]),

The symbol is referenced in the function _main. ”

2. As stated above, for Cpystr (char *des,const char *src) the parameter cpystr ("Hello", "Hello"), the first parameter of first argument const char * is converted to

char *, compilation can be passed. You need to use a function overload to define another function cpystr (const char *des,const char *SRC) to resolve.

Code Listing 2:

const char *a = "Hello";
char *b = A;

Code 2 cannot be compiled under VS2013, the error C2440: "Initialization": cannot be converted from "const char *" to "char *"

3. The above code 1 and code 2 are written in the C language compiled results are the same as the C + + compilation (test with GCC), but the C language cannot carry out function overloading to avoid this error.

Write C + + program to implement strcpy () function