CODEWITHSUNDEEP
lua
rocksrollsrules
rocksrollsrules

Reputation: 117

io.read() isn't working

I just started working on a very basic calculator program, and it works fine exempt I can't get it to keep the program open after it has completed the calculation. io.read() doesn't seem to work. My code is as follows:

promptmethod = "Would you like to use addition, subtraction, multiplication, or           division?"
promptnumber1 = "Enter a number:"
promptnumber2 = "Enter another number:"
anotherprompt = "Would you like to make another calculation?"

print(promptmethod)
usermethod = io.read("*line")
print(promptnumber1)
number1 = io.read("*number")
print(promptnumber2)
number2 = io.read("*number")

if usermethod == "addition" then
answer = number1 + number2
stringanswer = "Your calculation is " .. number1 .. " + " .. number2 .. " = " .. answer
elseif usermethod == "subtraction" then
answer = number1 - number2
stringanswer = "Your calculation is " .. number1 .. " - " .. number2 .. " = " .. answer
elseif usermethod == "multiplication" then
answer = number1 * number2
stringanswer = "Your calculation is " .. number1 .. " × " .. number2 .. " = " .. answer
elseif usermethod == "division" then
answer = number1 / number2
stringanswer = "Your calculation is " .. number1 .. " ÷ " .. number2 .. " = " .. answer
else
error("Invalid operation or values.")
end

print(stringanswer)

io.read()

Does anyone know why this would happen? Thank you!

Upvotes: 2

Views: 2325

Answers (1)

Mud
Mud

Reputation: 28991

A simpler example:

io.read('*number')
io.read()

The problem is that read('*number') does not consume the newline character after the number. Since that's still sitting on the input stream, so when you call io.read (which defaults to reading a line), it returns immediately.

To fix that, just call io.read a second time.

Upvotes: 4

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