I have two questions regarding C# -

in submitbutton_click method, i'm trying add code increase score 20 points every correct answer. reason not adding 20 points each time answer question correctly says 0. other question when 2 random variables change when click new , type in right answer marks incorrect. messing somewhere regarding these 2 problems?

here code

using system; using system.collections.generic; using system.componentmodel; using system.data; using system.drawing; using system.linq; using system.text; using system.threading.tasks; using system.windows.forms;  namespace lab4 {     public partial class lab4 : form     {         public lab4()         {             initializecomponent();             score = 0;          }          private int score = 0;         private int product = 0;         private int answer = 0;           private void submitbutton_click(object sender, eventargs e)         {              try             {                 answer = int.parse(answertextbox.text);                 if(convert.toint32(answertextbox.text)==product)                  {                      score=score+20;                     messagebox.show("correct!");                                    }                 else                 {                     messagebox.show("sorry, answer incorrect!");                 }              }             catch             {                 messagebox.show("there error processing answer!");             }          }            private void newbutton_click(object sender, eventargs e)         {              random rnd = new random();             int i, var1, var2, product;             var1 = rnd.next(1,9);             var2 = rnd.next(1,9);             promptlabel.text = ("what " + var1 +" . " + var2 + "?");             product = var1 * var2;             (i = 10; >= 1; i--)             {                 messagebox.show("you have " + + " sec(s) left!");                 timelabel.text = ("time: " + + " sec(s)");              }         }          private void scorelabel_click(object sender, eventargs e)         {          }          private void answertextbox_textchanged(object sender, eventargs e)         {          }     } } 

first problem have declared local variable inside method same name field in form class. both named product. local variable hiding field , therefore no value assigned product in class. have remove local 1 or have use this keyword tell compiler use field inside class.

you dont have declare product here because dont need it.

int i, var1, var2; //product; dont declare local variable. instead use field available var1 = rnd.next(1,9); var2 = rnd.next(1,9); promptlabel.text = ("what " + var1 +" . " + var2 + "?"); product = var1 * var2; // this.product = var1 * var2; 

another problem see timer. timer inside loop finishes instantly. because dont wait second countdown timer.

for (i = 10; >= 1; i--) {     messagebox.show("you have " + + " sec(s) left!");     timelabel.text = ("time: " + + " sec(s)");     await task.delay(1000); // wait 1 second } 

for have change signature of method async.

private async void newbutton_click(object sender, eventargs e) 

this maybe considered poor design count down timer. highly suggest take @ here know how correctly create count down timer.

https://msdn.microsoft.com/en-us/library/dd492144.aspx