Array Initialization using c++

Source code:
int main()
{
    //If the size is omitted, the compiler uses the number of values
    int days[12] = {31,28,31,30,31,30,31,31,30,31,30,31};

    // No initialization.
    float p1[1000];

    //To initialize an array to all zeros, initialize only the first value.
    // All 1000 values initialized to zero.
    float p2[1000] = {0.0};

    // Initial values of pressure(variable) undefined.
    float pressure[10];

    // Remaining characters zero.
    char greeting[100] = "Hello";

    // Array size is 6 (final zero on strings).
    char goodbye[] = "Adios";

    return 0;

}