fcvt and itoa differences?

[Adam Shapiro]

I posted earlier about problems using MessageBox (windows.h) with dynamic input from fcvt (string.h) and I found the problem. It seems that itoa requires the address of a character array while fcvt uses a character pointer. My question is: why? Aren't these two things theoretically the same other than a predefined amount of memory for the array?:

char *string1,string2[10];
string1="test";
string2="test";

The way I am looking at it, these should be the same. If this is the case, why does fcvt require string1 while itoa/ltoa requires string2?