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We use the standard algorithm input validation to check that the user is entering a value that is expected by the program. In the example below our function is used to check that the entered integer is between a max and min value.
def getValidInt(fMin,fMax): print("Please enter a number between",str(fMin), "and",str(fMax)) number=int(input()) while number<fMin or number>fMax: print("Sorry try again") print("Please enter a number between",str(fMin), "and",str(fMax)) number=int(input()) return number def main(): min=-100 max=100 number1=getValidInt(min,max) number2=getValidInt(1,20) print(number1,number2) main()
The function follows the AREA standard algorithm, that is Ask Repeat Error Ask. so
- Ask for valid number
- Repeat While number not valid
- Display Error
- Ask for valid number
Too remember this mnemonic easier think Jonathan Ross for step 2, as in Python we would use a While.
The code above makes use of local variables as well as formal and actual parameters. Can you spot them?