CODEWITHSUNDEEP
carrayscompiler-errors
maty ah
maty ah

Reputation: 13

cast specifies array type error with assaining two dimensional arrays in c

I have set a structure type:

typedef struct {
    char *snt[MAX_LINE_LENGTH];
} sentence;

And this line is getting a cast specifies array type error:

sentence copySentence(sentence *source) {
    sentence nw;
    nw.snt = (char *[])source->snt; //Here is the error
    return nw;
}

What is the best fix for this code line and what is the problem?

Upvotes: 0

Views: 1898

Answers (2)

nalzok
nalzok

Reputation: 16117

Both nw.snt and source->snt are arrays of pointer. To "deep copy" the whole array, you may want to use memmove(nw.snt, source->snt, MAX_LINE_LENGTH * sizeof (char *));.

Also, people usually prefer passing a pointer to a struct than pass that struct directly to reduce the cost of argument passing. In this case, you can

sentence *copySentence(sentence *source) {
    sentence *nw;
    nw = malloc(sizeof (struct sentence));
    memmove(nw.snt, source->snt, MAX_LINE_LENGTH * sizeof (char *));
    return nw;
}

Upvotes: 1

Paul Ogilvie
Paul Ogilvie

Reputation: 25286

You are declaring snt as an array of pointers to charactes. You probably mean it t be an array of charactes, or a pointer to an array of characters:

char snt[MAX_LINE_LENGTH];    // array of characters to hold your sentence
char *snt;                    // pointer to array of characters

When you assign an element to a compatible element, there is no need for a cast and casting is here considered harmful because you prevent the compiler from giving you warnings. Note that you do not copy the characters, you only make two structs point to the same sentence.

I leave fixing this to you, as an excercise.

Upvotes: 0

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