c# - Quick Search out of bounds of array and confusing array behaviour -
i'm having multiple problems program (c#.net) , have no idea what's causing them.
the program intended sort list of names , birthdays (formatted first name,last name,dd/mm/yyyy) in ascending , descending order first name, last name, , birthday. have other functions have not yet been implemented.
the first problem in quiksortstr method. program crashes in first if block, stating j out of bounds of array. happens whether or not mode == "asc".
the second, , more confusing problem when values loaded text file, every odd-indexed value of first , last null, while each odd-indexed value of bday 1/1/0001.
i've included full program below reference, quicksort method , use of parallel arrays required. apologies lack of comments.
thanks in advance help. i'm stumped.
namespace names_arrays { public partial class frmnamarrays : form { system.globalization.cultureinfo culture = new system.globalization.cultureinfo("en-ca"); string[] first; string[] last; datetime[] bday; string order = "asc"; string format = "d/m/yyyy"; public frmnamarrays() { initializecomponent(); } private void write() { string[] lines = new string[first.length]; (int = 0; < lines.length; i++) lines[i] = first[i] + ',' + last[i] + ',' + bday[i].tostring(format); txtbxnames.clear(); txtbxnames.lines = lines; } private void load() { string[] lines = txtbxnames.lines; first = new string[lines.length]; last = new string[lines.length]; bday = new datetime[lines.length]; int = 0; foreach (string line in lines) { string[] data = line.split(','); //there aren't lines split string[] of length less three, //but reason program kept believing there are. //patched leak. if (data.length == 3) { first[i] = data[0]; last[i] = data[1]; bday[i] = convert.todatetime(data[2], culture); } i++; } } public datetime[] quiksorttim(datetime[] primary, string mode, int left, int right) { if (primary.length > 1) { int = left, j = right; datetime pivot = primary[left + (right - left) / 2]; while (i <= j) { if (mode == "asc") { while (datetime.compare(primary[i], pivot) < 0) i++; while (datetime.compare(primary[j], pivot) > 0) j--; } else { while (datetime.compare(primary[i], pivot) > 0) i++; while (datetime.compare(primary[j], pivot) < 0) j--; } if (i <= j) { datetime holdoverb = primary[i]; primary[i++] = primary[j]; primary[j--] = holdoverb; string holdover = last[i - 1]; last[i] = last[j + 1]; last[j] = holdover; holdover = first[i - 1]; first[i] = first[j + 1]; first[j] = holdover; } } if (j > left) primary = quiksorttim(primary, mode, left, j); if (i < right) primary = quiksorttim(primary, mode, i, right); } return primary; } public string[] quiksortstr(string[] primary, string type, string mode, int left, int right) { if (primary.length > 1) { int = left, j = right; string pivot = primary[left + (right - left) / 2]; while (i <= j) { if (mode == "asc") { while (string.compare(primary[i], pivot) < 0) i++; while (string.compare(primary[j], pivot) > 0) j--; } else { while (string.compare(primary[i], pivot) > 0) i++; while (string.compare(primary[j], pivot) < 0) j--; } if (i <= j) { string holdover = primary[i]; primary[i] = primary[j]; primary[j] = holdover; if (type == "first") { holdover = last[i]; last[i] = last[j]; last[j] = holdover; } else { holdover = first[i]; first[i] = first[j]; first[j] = holdover; } datetime holdoverbeta = bday[i]; bday[i] = bday[j]; bday[j] = holdoverbeta; i++; j++; } } if (j > left) primary = quiksortstr(primary, type, mode, left, j); if (i < right) primary = quiksortstr(primary, type, mode, i, right); } return primary; } private void frmnamarrays_sizechanged(object sender, eventargs e) { txtbxnames.width = this.width - 40; txtbxnames.height = this.height - 157; } private void btnsort_click(object sender, eventargs e) { load(); switch (cbobxcategory.text) { case ("first name"): first = quiksortstr(first, "first", order, 0, first.length - 1); break; case ("last name"): last = quiksortstr(last, "last", order, 0, last.length - 1); break; case ("birthday"): bday = quiksorttim(bday, order, 0, bday.length - 1); break; default: break; } write(); } private void cbobxorder_selectedindexchanged(object sender, eventargs e) { if (cbobxorder.text == "ascending") order = "asc"; else order = "desc"; } private void displayfile(string name) { streamreader filedata = new streamreader(name); txtbxnames.lines = filedata.readtoend().split('\n'); } private void mnuopen_click(object sender, eventargs e) { openfiledialog open = new openfiledialog(); open.filter = "text files|*.txt"; open.title = "select text file..."; if (open.showdialog() == dialogresult.ok && open.filename != "") displayfile(open.filename); } private void mnuexit_click(object sender, eventargs e) { this.close(); } } }
you have change code below in quiksortstr method inside if (i <= j) loop
datetime holdoverbeta = bday[i]; bday[i] = bday[j]; bday[j] = holdoverbeta; i++; j--;//was: j++; and fix issue.
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