Why does using square brackets cause a subscripted value is neither array nor pointer nor vector error?

Question

I'm new to C and I'm trying to become familiar with the basics, I thought id make a program that just takes an array and uses a function to print the information in the array. However, when I try to compile this program I get the following error:

error: subscripted value is neither array nor pointer nor vector
           printf(" %d", data[i]);
                             ^

The code I'm currently using is below:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int maxReturn(int a, int b, int c, int d);

int main(){

    int arr[4] = {1,4,8,2};

    int max = maxReturn(arr[0],arr[1],arr[2],arr[3]);

    printf("%d\n", max);

    return 0;
}

int maxReturn(int a, int b, int c, int d){

    int data = {a,b,c,d};
    
    for(int i; i < 4; i++){
        printf(" %d", data[i]);
    }
    printf("\n");
    
    return data;

}

I'm at a bit of a loss as to what is wrong here because in the tutorials I'm following they print out values by using data[i]. Why is this not ok?

Answer 1

You are declaring an int using the {...} construct as if you were initializing an array. Probably, you forgot to declare data as an array of int .

Replacing the line:

int data = {a,b,c,d};

with:

int data[4] = {a,b,c,d};

should fix your problem.

EDIT:

You might not even define the size of the array in this case, because using the {...} construct the compiler computes the size of the array at build-time.