I am stuck with variables
private void button1_Click(object sender, EventArgs e)
{
char op;
int first, second, result;
first = Convert.ToInt32(textBox1.Text); second = Convert.ToInt32(textBox2.Text); result = Convert.ToInt32(textBox4.Text); op = Convert.ToChar(textBox3.Text); switch (op) { case '+': result = first + second; break; case '-': result = first - second; break; case '*': result = first * second; break; case '/': result = first / second; break; default: textBox3.Text = "Invalid Operator!"; break; } } I am trying to build a calculator with using the switches, my goal to take the user input from textbox 1 and 2 and by using the switches calculate the result. However, whenever I start the program it says "The input string was not correct" for the result line. I tried to convert it to int and double but it didn't work and I am simply stuck, how can I solve it?
first = Convert.ToInt32(textBox1.Text); second = Convert.ToInt32(textBox2.Text); result = Convert.ToInt32(textBox4.Text); op = Convert.ToChar(textBox3.Text); switch (op) { case '+': result = first + second; break; case '-': result = first - second; break; case '*': result = first * second; break; case '/': result = first / second; break; default: textBox3.Text = "Invalid Operator!"; break; } } I am trying to build a calculator with using the switches, my goal to take the user input from textbox 1 and 2 and by using the switches calculate the result. However, whenever I start the program it says "The input string was not correct" for the result line. I tried to convert it to int and double but it didn't work and I am simply stuck, how can I solve it?
4 Replies
Probably because
textBox4.Text is empty
An empty string is not a number
So Convert throws an exception
From what I see, textBox4 is where the result should go, it has no initial value, so there's no need to even try to convert it to a number
@RXPHXELYep textbox 4 is empty
How can I rewrite the code then
Don't get the
result
Make the result an empty int variable, for example
And only at the end, after the switch, assign its value to textBox4.Text
textBox4.Text = $"The result is {result}"; for exampleThank you so much