Arrays - in COBOL and C#

01 nums binary-long occurs 3 values 1, 2, 3.  *> reference single-dimensional array

01 names1 string occurs 5. *> 5 is the size of the array
01 names2 string occurs any. *> size of array deferred until run-time
01 names3 string occurs 7.
01 names4 string occurs any.
01 twoD float-short occurs any, any.  *> 2-dimensional (rectangular) array
01 jagged binary-long occurs any, occurs any.  *> 2-dimensional (jagged) array

01 rows binary-short value 4.
01 cols binary-short value 3.

procedure division.

*> another way to reference an array
set content of nums to (1, 2, 3)  

*> another way to set size of array
set size of names1 to 5  
set names1(1) to "Rod"  *> first element indexed as 1
set names1(6) to "Jane"  *> throws System.IndexOutOfRangeException

*> resizing arrays
*> resizes array by assigning reference to new array - current contents are lost to the garbage collector 
set size of names1 to 10  
*> to retain existing values, copy the array into a new array of the required size
invoke type Array::Copy(names1, names3, size of names3) *> copies array, maintaining its contents
*> or:
invoke type Array::Resize(names1,10)  *> resizes array, retaining existing index values
*> or:
set size of names4 to size of names1
invoke names1::CopyTo(names4, 0)

 *> 2-dimensional arrays
 set size of twoD to rows, cols
 set size of jagged to 3
 set size of jagged(1) to 5
 set jagged(1 5) to 5  

int[] nums = {1, 2, 3};
for (int i = 0; i < nums.Length; i++)
{
   Console.WriteLine(nums[i]);
}
 
// 5 is the size of the array
string[] names = new string[5];
names[0] = "Rod";
names[5] = "Jane";   // Throws System.IndexOutOfRangeException 
 
 
// C# can't dynamically resize an array.  Just copy into new array.
string[] names2 = new string[7]; 
// or names.CopyTo(names2, 0); 
Array.Copy(names, names2, names.Length);
 
 
 
float[,] twoD = new float[rows, cols];
twoD[2,0] = 4.5f; 
 
int[][] jagged = new int[3][] { 
  new int[5], new int[2], new int[3] };
jagged[0][4] = 5;

Portions of these examples were produced by Dr. Frank McCown, Harding University Computer Science Dept, and are licensed under a Creative Commons License.