#! /usr/bin/python # We'll print these strings at the appropriate time HTML_HEADER = 'Content-type: text/html\n\n' Top_HTML = ''' ''' Bottom_HTML = '

The answers...

' Nothing_Requested = 'No answers were requested' Bad_Arithmetic = 'Error: We needed two numbers to work on, and NO DIVIDING BY ZERO!' Bad_String = 'Error: We needed a string for string processing!' # We need these library modules to retrieve the user's answers import cgi # We need this module to debug Python program bugs import cgitb cgitb.enable() def main(): print HTML_HEADER print Top_HTML # ask the library function to retrieve all answers and put them # into a dictionary form = cgi.FieldStorage() if not form.has_key('CheckArithmetic') and not form.has_key('CheckString'): # the user hasn't requested either arithmetic or string processing print Nothing_Requested else: if form.has_key('CheckArithmetic'): if not ArithmeticQuestionsAreGood(form): print Bad_Arithmetic else: question = 'The question is: '+form['FirstNum'].value+form['Operator'].value+form['SecondNum'].value fnum = int(form['FirstNum'].value) snum = int(form['SecondNum'].value) op = form['Operator'].value if op == '-': answer = fnum - snum elif op == '+': answer = fnum + snum elif op == '*': answer = fnum * snum elif op == '/': answer = fnum / snum print ''+question+' The answer is: '+str(answer)+'' if form.has_key('CheckString'): # Did the user provide a string? if not form.has_key('TheString'): print Bad_String else: s = form['TheString'].value rad = form['RadioString'].value if rad == 'Lower': question = 'lower-case' answer = s.lower() elif rad == 'Upper': question = 'upper-case' answer = s.upper() print 'Convert "'+s+'" to '+question+': "'+answer+'"' print Bottom_HTML def ArithmeticQuestionsAreGood(f): # Did the user actually provide numeric requests (or is either blank)? if not f.has_key('FirstNum') or not f.has_key('SecondNum'): return False s1=f['FirstNum'].value s2=f['SecondNum'].value if s1 == '' or s2 == '': return False # Are they numbers? if not s1.isdigit() or not s2.isdigit(): return False op = f['Operator'].value num_s = int(s2) if num_s == 0 and op == '/': return False # divide by zero? return True # OK, run the main() function... main()