Find c Programmatically add two numbers and display the sum, handling the input error with an except

I don't understand what you mean by this particular case, if you mean an invalid input, such as entering a letter, then in int a = ;

int b = ;

When entering letters, these two lines will directly report an error causing the program to be interrupted, the correct should be to put the check in front, check through and then convert to an integer, because there are too many errors in your program (including the for check is also problematic, if the length of the two numbers is inconsistent), basically to completely rewrite, consider the following.

protected void unnamed1_click(object sender, eventargs e)

int a=0,b=0;

if(,out a)

if(,out b)) = (a + b).tostring();

else "The number entered in text box 2 is invalid, please re-enter it");

The number entered in the else text box 1 is invalid, please re-enter it");}

int a = ;

int b = ;

Move the above two lines to if (flag == 0) and go to if (flag == 0).

Otherwise, as long as you enter the box with non-numbers, these two lines will be wrong, and you will not be judged down.

int a = ;

If you enter a number other than a number, an exception will occur.

substitution: int a=0;

bool isnumber = ,out a);

If you don't sell acres in the try block, how to catch formatexception?

What you manually threw should be throw new overflowexception() overflow.

What type of control receives input?

using system;

using ;

using ;

using ;

namespace exp05_01

Please enter your answer:");

int ret = 0;

if (,out ret))

elseelse

else}}

Press any key to start the next one, enter'e'Come to an end! ");

while ( = "e");}

Can you be more detailed? Do you want to enter an expression that the program automatically determines ture or false?

Go to the verification in your button click event.

Remove all of these, don't you know how to use events?

prviate void txtname_enter（object sender，canceleventargs e）

prviate void txtname_validating（object sender，canceleventargs e）

prviate void txtpassword_enter（object sender，canceleventargs e）

prviate void txtpassword_validating（object sender，canceleventargs e）

1 All foreach (type identifier in expression).

foreach (type identifier in expression ).

The usage of foreach is as above, and the specifics are:

list lists=new list();

foreach(int i in lists)

Missing a semicolon? You put a semicolon; Try adding to the last parentheses.

using ;

string a = "";

string b = "";

string c = "";

string d = "";

int max1 = 0;

int max2 = 0;

int max = 0;

a = ;while (!isnum(a))

b = ;while (!isnum(b))

c = ;while (!isnum(c))

d = ;while (!isnum(d))

max1 = >

max2 = >

max = max1 > max2 ? max1 : max2;

The maximum number is:", max);

Press any key to exit! ");

public static bool isnum(string s)

Written in a notepad. Not tested.

Is this question still useful? Still asking?! First of all, are your numbers entered separately or lost together?!

Let's not talk about the few parameters entered separately, if you lose them together, please use them","number, and then use the list <> to disassemble, and verify the numbers separately to understand that the first number is wrong, and there are many ways to verify the data, such as regular expression validation.

Quote using;

public static bool isnumber(string num)

if (num ==

if (num == "0")

regex rg = new regex("^[0-9]*[1-9][0-9]*$");

if (else

This verification is 100% fine, though"^[0-9]*[1-9][0-9]*$"This regular expression is to verify positive integers, if you have negative decimal or something, you can look for the relevant regular expression, there are many on the Internet.