PRO VAL_COUNT,A,x,count,ROWS=rows
;+
; QUESTION 1
; You should write the necessary IDL statements
; to complete this procedure. After you have thoroughly
; tested the procedure and inserted your comments in
; the code, please use the simg211-submit tool to
; submit the results.
;
; By submitting this procedure for a grade you
; attest that this is your own work.
;
; PURPOSE
; This procedure counts the number of times the value
; given by x appears in rows of an array A. If the
; value of rows is not specified then all the count is
; given for every row.
;
; USAGE EXAMPLE:
; Assume that A is an array with 4 rows and you
; want to know the number of times that the value
; 2 occurs in each row.
;
; The array A in this example is
; 1 2 1 2 1 2 1 2 1 2
; 2 1 2 1 2 1 2 1 2 1
; 1 2 3 1 2 3 1 2 3 1
; 3 2 1 3 2 1 3 2 1 3
;
; VAL_COUNT,A,2,count
; PRINT,'count=',count
;
; The result should be
; count=5,5,3,3
;
; Suppose that you want to know the number of times
; that 2 occurs in 0 and 3. Then use
;
; rows=[0,3]
; VAL_COUNT,A,2,count,ROWS=rows
; PRINT,' rows=',rows
; PRINT,'count=',count
;
; The result should be
;  rows=0,3
; count=5,3
;
; NOTE: The program should work even if A has only
; one column.
;
; NOTE: The program should return -1 if the number
; of dimensions of A is not 1 or 2.
;
; HINT
; You can test whether a value has been assigned to
; cols by using the function N_ELEMENTS(rows). If
; N_ELEMENTS(rows) is less than or equal to zero then
; you have search all rows.
;
; PROGRAMMED BY:
;
; DATE:
;-