int maxSize;
var longer = null;
if (array1.Length > array2.Length) {
    maxSize = array2.Length;
    longer = array1;
} else {
    maxSize = array1.Length;
    longer = array2;
}
for (i = 0; i < maxSize; i++) {
    Console.Write(array1[i], "|", array2[i], " ");
}
if (longer.Length > maxSize) {
for (i = maxLength; i < longer.Length; i++) {
    Console.Write(array1[i], " ");
}