Question

Why is this while loop not ending when the proper input is entered (a number between 0 and 100)

grade = 110
invalid_input = 1
while grade< 0 or grade> 100:
    if invalid_input >=2:
        print "This is an invalid entry"
        print "Please enter a number between 0 and 100"
    grade= raw_input("Please enter your marks for Maths : ")
    invalid_input +=1

what ever i put in be it a number or text the (this is an invalid entry , Please enter a number between 0 and 100
does anyone one know what is wrong?

Answer 1

in grade=raw_input("Please enter your marks for Maths : "), grade is a string, not number. try

grade = int(raw_input("Please enter your marks for Maths : "))

In order to prevent the program from being terminated if the user makes a wrong input, you will need to use a exceptions, like this

grade = 110
invalid_input = 1
while grade< 0 or grade> 100:
    if invalid_input >=2:
        print "This is an invalid entry"
        print "Please enter a number between 0 and 100"
    try:
      grade= int(raw_input("Please enter your marks for Maths : "))
    except ValueError:
      grade = -1  # just to enter another iteration
    invalid_input +=1