1. Arrays and Strings
CSCI293 - C#
September 26, 2005

2. Refresher: declaring arrays
int[] myarray = new int [10];
Step One - declare myarray to be a variable holding a list of integers
Step Two - allocate space for myarray

3. The foreach Statement float[] bob = {1.1f, 2.2f, 3.3f, 4.4f,
for (int i=0; i < bob.Length; i++)
Console.WriteLine ("{0}", bob[i]);
foreach (float x in bob)
Console.WriteLine ("{0}", x);

4. Multi-Dimensional Arrays
Each dimension of a multi-dimension array can be the same (like in C++)
for example, 5 rows each of length 10
int[][] myArray = new int[5][10];
Each dimension can be a different size
first row's length is 10, but second row's length is 15
int[][] myWeirdArray = new int[2][];
myWeirdArray[0] = new int[10];
myWeirdArray[1] = new int[15];

5. Passing Arrays as Parameters
public int largest (params int[] thelist) {
int max = thelist[0];
foreach (int value in thelist)
if (value > max)
max = value;
return max; }
Then inside main():
Class1 tempvar = new Class1();
int largest;
int[] myarray = {8,2,3,9,4};
largest = tempvar.largest (myarray);
Console.WriteLine ("largest = {0}", largest);
largest = tempvar.largest (10, 40, 20, 30);

6. Sorting and Searching Array.Sort (myarray);
Console.Write ("sorted array = ");
foreach (float value in myarray)
Console.Write("{0} ",value);
Console.WriteLine();
int index = Array.BinarySearch(myarray,4);
Console.WriteLine("4 is at array index {0}", index);

7. Other Array Functions // you don't need a for loop to copy an array
Array.Copy(oldarray,0,newarray,0,oldarray.Length);
// reverse an array
Array.Reverse (myarray);
//how long is the array?
for (int i=0; i<myarray.Length; i++)
// where is the value 99 in my list?
location = Array.IndexOf (myarray, 99);

8. Creating Strings string name1 = "Steve Dannelly";
string name2 = "BOB";

9. Comparing Strings
Unlike C++, where you must use strcmp to compare the contents of two strings, in C# you can use ==
if (name2 == name2.ToUpper())
Console.WriteLine("all uppercase");
else
Console.WriteLine("not uppercase");
But, you still can not use < or >
if (string.Compare(name1,name2) < 0)
Console.Write("name1 < name2");

10. Other String Functions
Length
Copy
PadLeft
PadRight +
Note that "string" ≠ "char[]". So the list of string methods is different from the list of array methods
for example, there is no string.reverse
but you can do this: mystring[0] = 'A';