array problem

[voklta7]

The following piece of code is valid in c :

#include <stdio.h>

int main(int argc, const char * argv[])
{
    int array1 = {1,2,3,4,5};
    int array2[] = {1,2,3,4,5};
    int array3[5] = {1,2,3,4,5};
}

I know array1 is a single int and array2 and array3 are actual arrays , but what is the use of statement

int array1 = {1,2,3,4,5};

why is it valid ? whats the use ?