Thread: about decleration?

hello

please can someone tell me

is it ok to write

char *s = "hello";

or to write

char *s;
s = "hello";

i want to know what is the difference

what about

int *i = 7; is it acceptable? and what will it do?

Thanks

char* s = "hello"; // is acceptable
char* s;
s = "hello world"; // Not allowed.

int* i = 7; // assigns i to point to address 7; not acceptable or clear code

hi

thank you for your response

you said that

char* s;
s = "hello world"; // Not allowed

i've compiled it and there were no errors

so why it's not allowed? what will it do?

It is not a part of the standard. It is assigning a const array of chars to a pointer to char variable.

It actually *is* legal, and it works quite nicely, but however, there should be a change to BOTH pieces of code:

const char *s = "hello";

const char *s;
s = "hello";

The second is fully legal; the type of a string literal is "const char *" so it is fully legal. Without the const, it still works, but this is a bad thing to use -- this is the only instance in C++ of an automatic cast from a const to a non-const, and, like ANY cast from const, it can easily be abused.

In fact, the cast is listed as deprecated, so new code should never use it; it may be phased out eventually.

This, however, is NOT legal:

char arr[6];
arr = "hello";