CODEWITHSUNDEEP
carraysfunctionpointers
Stewart
Stewart

Reputation: 3161

Iterating over an array that has been passed by reference in c

I wish to write an print array function in c. I have herd when you pass an array to a c function via reference it passes a pointer to the first element. I am assuming that I can increment this pointer to iterate over the array however my program just segfaults.

I would like to know firstly why my program is seg faulting and also what the most idiomatic approach to writing a function like this in c. Thanks in adavnce.

void print_array(int *array, int length) {
    int i = 0; 
    for (i = 0; i < length; array++) {
        printf("%d\n", *array);
    }
}

int main (int argc, int *argv[]) {
    int test[10] = {0};
    print_array(test, 10);
}

Upvotes: 2

Views: 2320

Answers (2)

autistic
autistic

Reputation: 15632

Your loop is infinite, because i in i < length never changes; That condition always evaluates true. As a result, you're jumping past the end of the loop. I suggest changing your loop to:

for (i = 0; i < length; i++) {
    printf("%d\n", array[i]);
}

... or, if you wish to use array++, change the condition:

for (int *end = array + length; array < end; array++) {
    printf("%d\n", *array);
}

Upvotes: 4

Parker Kemp
Parker Kemp

Reputation: 765

Try this:

void print_array(int *array, int length) {
    int i = 0; 
    for (i = 0; i < length; i++) {
        printf("%d\n", array[i]);
    }
}

Since i is your loop control variable (it's in the loop condition), you need to increment it to avoid an infinite loop. And using the [] notation is much easier to grasp for someone at your level than trying to increment the pointer manually.

Upvotes: 0

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