Cleveland State University. Lecture Notes Feb Iteration Arrays ArrayLists. V. Matos

Transcription

1 Cleveland State University IST311 V. Matos Lecture Notes Feb Iteration Arrays ArrayLists Observe that various ideas discussed in class are given as separate code fragments in one large file. You need to toggle comments to execute the different portions of these notes. ITERATION ARRAYS. Chapter SAMPLE #1 using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace Looping1 class Program static void Main(string[] args) // reading three-digits data from the system's keyboard // (data set ends with -1) // Find max, min, and average int data = 0; string strdata; int samplemax = -1; int samplemin= 1000; int sampleaccumulator = 0; int samplesize = 0; double sampleavg = 0; while (data!= -1) Console.WriteLine("Enter a number [-1 to END]"); strdata = Console.ReadLine(); data = int.parse(strdata); if ((data >= 0) && (data <= 999)) samplesize++; sampleaccumulator += data; //choosing MINIMUM value if (data < samplemin) samplemin = data; //choosing MAXIMUM if (data > samplemax) samplemax = data; else String msg = data == -1? "" : "Invalid data"; Console.WriteLine(msg);

2 //while //showing results if (samplesize > 0) Console.WriteLine("Max value: " + samplemax); Console.WriteLine("Min value: " + samplemin); Console.WriteLine("Avg value: " + (double)sampleaccumulator/samplesize); Console.WriteLine("Done..."); Console.ReadLine(); SAMPLE #2 using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace Looping2 class Program static void Main(string[] args) // different forms of the for loop int j = 3; for (int i1 = 0; i1 <= j; i1++) Console.WriteLine("i= 0 j=1", i1, j); // //int i2 = 0; //for ( ; i2 <= 3; i2++) // // Console.WriteLine("i2= 0 ", i2 ); // // //int i3 = 0; //for (; true ; ) // // Console.WriteLine("i3= 0 ", i3++); // if (i3 > 4) break; // Console.WriteLine("Done..."); Console.ReadLine(); //main //program

3 ARRAYS CHAPTER 7. Arrays & List Arrays using System; using System.Collections.Generic; using System.Collections; using System.Linq; using System.Text; namespace Arrays1 class Program static void Main(string[] args) //// //int[] a = new int[3]; //a[0] = 11; //a[1] = 22; //a[2] = 33; ////a[4] = 44; // // // Console.WriteLine("a[0]= 1", i, a[i]); // //// //int[] b = new int[] 111, 222, 333, 444 ; //for (int i = 0; i < b.length; i++) // // Console.WriteLine("b[0]= 1", i, b[i]); // ////is the following a mistake? ////Console.WriteLine( b[4] ); ////is the following a mistake? ////int i = 3; ////// ////enter n values. compute avg and difference to avg. //double accumulator = 0.0; //int n = 5; //int[] c = new int[5]; //for (int i = 0; i < c.length; i++) // // Console.WriteLine("Enter a number"); // c[i] = Convert.ToInt32(Console.ReadLine()); // accumulator += c[i]; // //double avg = (double)accumulator / n; //Console.WriteLine("Average is: " + avg); //for (int i = 0; i < c.length; i++) // // Console.WriteLine("0\t1\t2", i, c[i], (c[i] - avg)); // //// //// testing foreach loop //int[] b = new int[] 111, 222, 333, 444 ; //foreach (int x in b) // // Console.WriteLine("foreach loop. " + x);

4 // // //copying from one array to another (to discuss later) //int[] d = new int[] 22, 11, 33, 44 ; //int[] e = new int[d.length]; //e = d; // this is a SHALLOW copy //foreach (int x in e) Console.WriteLine("Shallow1 " + x); //d[3] = 44444; //foreach (int x in e) Console.WriteLine("Shallow2 " + x); //for (int i = 0; i < d.length; i++) // // e[i] = d[i]; //this is a DEEP copy // //foreach (int x in e) Console.WriteLine("Deep1 " + x); //d[3] = ; //foreach (int x in e) Console.WriteLine("Deep2 " + x); //// ////using methods in the Array Class (sorting searching...) //int[] f = new int[] 55, 33, 11, 22, 44 ; //Console.WriteLine("\nArray Data"); //foreach (int x in f) Console.Write("\t" + x); //Array.Sort(f); //Console.WriteLine("\nArray.Sort"); //foreach (int x in f) Console.Write("\t" + x); //Array.Reverse(f); //Console.WriteLine("\nArray.Reverse"); //foreach (int x in f) Console.Write("\t" + x); //Console.WriteLine("\nArray.Index of 22: " + Array.IndexOf(f, 22)); //Console.WriteLine("\nArray.Index of 99: " + Array.IndexOf(f, 99)); //int[] g = new int[f.length]; //Array.Copy(f, g, f.length); //this is a DEEP copy //Console.WriteLine("\nArray.Copy1"); //foreach (int x in g) Console.Write("\t" + x); //f[0] = ; //Console.WriteLine("\nArray.Copy2"); //foreach (int x in g) Console.Write("\t" + x); ////Array.Clear(g, 0, g.length); ////Console.WriteLine("\nArray.Clear"); ////foreach (int x in g) Console.Write("\t" + x); //// ////passing an array as a parameter (byreference) //int[ ] h = new int[ ] 55, 33, 11, 22, 44 ; //MyNiceArrayDisplay(h); //foreach (int x in h) // Console.WriteLine(x); //// ////passing an array as a parameter (byreference) & method changing data

5 //int[] m = new int[] 55, 33, 11, 22, 44 ; //Console.WriteLine("[Main] Array Before calling Method"); //foreach (int x in m) Console.Write("\t" + x); //int b = 5; //MyMethodChanger(m, b); //Console.WriteLine("[Main] Array After calling Method"); //foreach (int x in m) Console.Write("\t" + x); //Console.WriteLine(); //Console.WriteLine("Value of b: " + b); // //passing an array as a parameter (byreference) & method returning data //int[ ] n = new int[ ] 55, 33, 11, 22, 44 ; //int searchvalue = 99; //int location = MyFindDataInArrayMethod(n, searchvalue); //Console.WriteLine("Value 0 at Location: 1", searchvalue, location); //for(int i = 0; i <n.length; i++) // Console.WriteLine("Loc 0: 1", i, n[i]); //try int searchvalue = 99; //// //// count ODD numbers //int[ ] n = new int[ ] 55, 33, 11, 22, 44 ; //int countodd = MyCountOddMethod(n); //Console.WriteLine("There are 0 ODD numbers in the array", countodd); //for (int i = 0; i < n.length; i++) // Console.WriteLine("Loc 0: 1", i, n[i]); // // count how many numbers below the array's average, return percent value int[] n = new int[] 55, 33, 11, 22, 44 ; double pctbelow = MyBelowAvgMethod(n); Console.WriteLine("Percentage of cells below avg is 0", pctbelow); for (int i = 0; i < n.length; i++) Console.WriteLine("Loc 0: 1", i, n[i]); //// //// two dimensional arrays //int[,] golfstrokes1 = new int[18, 2]; //RECTANGULAR (strokes,putts) //int[,] scoreboard = new int[,] 25, 33, 48, 62, 69, 78, 82, 101 ; //scoreboard[3, 0] = 82; //accessing cells of RECTANGULAR array //scoreboard[3, 1] = 101; //for (int row=0; row<4; row++) // // Console.Write("\nQuarter 0 ", row);

6 // for(int col=0; col<2; col++) // // Console.Write("\t" + scoreboard[row, col]); // // //// //int[ ][ ] calories = new int[7][ ]; //JAGGED array //calories[0] = new int[ ] 900, 1200, 1000 ; //calories[1] = new int[ ] 800, 1800 ; //calories[2] = new int[ ] 5000 ; //calories[3] = new int[ ] 900, 1300, 1400 ; //calories[4] = new int[ ] 800, 1100 ; //calories[5] = new int[ ] 950, 1400 ; //calories[6] = new int[ ] 1200, 1000, 1800 ; //calories[6][0] = 1200; //accessing cells of JAGGED array ////calories[6, 0] = 1200; //invalid statement //for (int row = 0; row < 7; row++) // // Console.Write("\nCalories-Day 0", row); // foreach( int x in calories[row] ) // // Console.Write("\t0", x); // // ////using the Rank method to determine the array's dimension //Console.WriteLine("\n"); //Console.WriteLine("Calories.RANK " + calories.rank); //Console.WriteLine("Calories.GETLENGHT(0) " + calories.getlength(0) ); //Console.WriteLine("\n"); //Console.WriteLine("scoreBoard.RANK " + scoreboard.rank); //Console.WriteLine("scoreBoard.GETLENGHT(0) " + scoreboard.getlength(0)); //Console.WriteLine("scoreBoard.GETLENGHT(1) " + scoreboard.getlength(1)); //// //// ArrayList (Dynamic arrays) //// ADD: using System.Collections; //// Creates and initializes a new ArrayList. //ArrayList myal = new ArrayList(); //myal.add("hello"); //myal.add("wonderful"); //myal.add("world"); //myal.add("!"); //myal.add("adios"); //myal.add(123); //myal.add(1); //// Displays the properties and values of the ArrayList. //Console.WriteLine("myAL ArrayList"); //Console.WriteLine("\tCount: 0", myal.count); //Console.WriteLine("\tCapacity: 0", myal.capacity); //Console.WriteLine("\tValues:"); //for (int i = 0; i < myal.count; i++) // // Console.WriteLine("\t0: 1 \t\ttype: 2", // i, myal[i], myal[i].gettype()); // //Console.WriteLine("\t0: 1 " // // + (myal[i].tostring().length<4?"\t\t":"\t") // // + " Type: 2", // // i, myal[i], myal[i].gettype());

7 // //Console.WriteLine("Contains World: " + myal.contains("world")); //Console.WriteLine("IndexOf World: " + myal.indexof("world")); //Console.WriteLine("After Insert"); //myal.insert(2, "blue"); //for (int i = 0; i < myal.count; i++) // // Console.WriteLine("\t0: 1 ", i, myal[i]); // //Console.WriteLine("After Remove"); //myal.remove("wonderful"); //for (int i = 0; i < myal.count; i++) // // Console.WriteLine("\t0: 1 ", i, myal[i]); // //Console.WriteLine("After RemoveAt last"); //myal.removeat(myal.count - 1); //for (int i = 0; i < myal.count; i++) // // Console.WriteLine("\t0: 1 ", i, myal[i]); // /////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // STRINGS /////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// //String str1 = "Hello woderful world"; //String str2 = ""; //String str3; //String str4 = "Hello WONDERFUL World"; //Console.WriteLine("\nstr1 is: 0", str1); //Console.WriteLine("str1 Length: 0", str1.length ); //Console.WriteLine("str1 first char: 0", str1[0] ); //Console.WriteLine("str1 last char: 0", str1[ str1.length-1 ] ); //Console.WriteLine("str1 IndexOf(a): 0", str1.indexof("a") ); //Console.WriteLine("str1 IndexOf(u): 0", str1.indexof("u")); //Console.WriteLine("str1 LastIndexOf(o): 0", str1.lastindexof("o")); //Console.WriteLine("str1.Replace : 0", str1.replace("world", "mundo")); //Console.WriteLine("str1 Substring: 0", str1.substring(7, 3) ); //string[] tokens = str1.split(); //Console.WriteLine("Number of tokens after Split() 0", tokens.length); //for (int i=0; i < tokens.length; i++) // Console.WriteLine("After Split - tokens[0]= 1", i, tokens[i] ); //String strwithmanyblanks = " Adios amigos "; //Console.WriteLine("strWithManyBlanks: *0* \n After Trimming: *1*", // strwithmanyblanks, strwithmanyblanks.trim() ); //Console.WriteLine("ToUpper: 0", strwithmanyblanks.toupper() ); // //assignment //str2 = str1; //Console.WriteLine("\nstring str2= 0", str2); ////comparison (remember == does not work for strings) //if (str1.compareto(str4) == 0) // Console.WriteLine("0 -is greather than- 1", str1, str4); //else // Console.WriteLine("0 -is greather than- 1", str4, str1);

8 //Console.WriteLine(".compareTo(...) value is: " + str1.compareto(str4)); // Console.WriteLine("\nDone..."); Console.ReadLine(); //main // private static void MyNiceArrayDisplay (int[ ] a) Console.WriteLine("cell[0]= 1", i, a[i]); a[i] += 10; // private static void MyMethodChanger(int[ ] a, int b) Console.WriteLine("\n[Method] Array received by the subroutine"); Console.Write("\t" + a[i]); a[i] += 10; //each array cell is changed b = 1000; Console.WriteLine(); // public static int MyFindDataInArrayMethod(int[] m, int valuetobefound) for (int i = 0; i < m.length; i++) if (m[i] == valuetobefound) return i; return -1; // // counting odd numbers in an array public static int MyCountOddMethod(int[] a) int accum = 0; if (a[i] % 2 == 1 ) accum++; return accum; // // percent of values below avg public static double MyBelowAvgMethod(int[] a) int accum = 0; accum = +a[i]; double avg = (double) accum / a.length; int countbelow = 0; if (a[i] < avg) countbelow++;

9 return (double)(countbelow / a.length); // NEEDS TO BE FIXED??? //program