Trouble calling function from CLI

[brett13]

Just a heads up that this code could potentially corrupt memory. It only reserves 8 characters (7 chars plus the null character) for the array pointed to by msg in the line

char msg[] = "DEFAULT";

The function changeMessage copies the contents of newMessage into the array even if changeMessage contains more than 8 characters. This will lead to memory issues.

Refer to this excellent post (another post latter in the thread, by Zachary, gives a great intro to C strings):

@zachary

Good question @flashyourface! This is a basic thing in C/C++, but I totally get how it's confusing from a web language!

Two things need to change.

Reserve memory for the string

Strings take up a variable amount of space. Each letter adds more memory that you need to reserve. The word used by C programmers for this is that you have to "allocate" memory for the string.

At the top, change char *msg; which only allocates enough space for the pointer to the string to char msg[100]; to reserve space for up to 99 characters. C strings always end with a null byte.

Use strcpy instead of equals

To make a copy of a string variable in C, you should use the strcpy function. Also String objects have a c_str() method to pull out the char*, so you should do this:

strcpy(msg, message.c_str());

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Your integer code should work fine! What error are you getting?

@flashyourface I know you've already seen this, but I thought it would improve this thread to reference it.