Question

I am having a problem with the following code and I cannot figure it out? If anyone has any ideas, please let me know.

I have two global variables:

char *newArgv[100], *s[MAXCHAR];

and one function

getword(char *w)

in my main function, I make a call to this function by saying

getword(s[num]);

and in the getword function, I have an assignment that says something like

w[index] = 'e';

The problem is in that last line of code. The project compiles (obviously) but the program crashes. Anyone have any ideas why? Thanks!

Answer 1

You’re dereferencing a NULL pointer.

s is an array of MAXCHAR NULL pointers. s[num] returns the numth pointer – which is also NULL. So inside getword, w[index] is illegal.

You’ll need to allocate memory dynamically:

for ( int i = 0 ; i < MAXCHAR ; i++ )
    s[i] = malloc(MAX_WORD_LENGTH);