Was doing some multiple choices and one question gave the following array definitions and asking which are valid statements:
int[] array1, array2[];
int[][] array3;
int[] array4[], array5[];
A. array2 = array3;
B. array2 = array4;
C. array1 = array2;
D. array4 = array1;
E. array5 = array3;
And the correct answers are A,B,E. Why? I see array3 and array4 are 2 dimensional arrays and array1,2,5 are not.
Split the definition of each variable per line and then you will realize how each operation compiles (or not):
int[] array1;
int[] array2[]; //which is int[][] array2
int[][] array3;
int[] array4[]; //which is int[][] array4
int[] array5[]; //which is int[][] array5
Now, you can easily evaluate these:
A. array2 = array3; //compiles
B. array2 = array4; //compiles
C. array1 = array2; //doesn't compile
D. array4 = array1; //doesn't compile
E. array5 = array3; //compiles
Also, in Java, there are not 2 dimensional arrays. You have array of arrays.
int[] array1, array2[];
int[][] array3;
int[] array4[], array5[];
array1 is a single dimension array
array2 is now a 2dimension array as well as array4 and array 5 array3 is also declared as a 2d array
array 1 does not equal any other array in the list
array 2 can = array3, array4, or array5 and vice versa.
