5.4 Solutions

  1.  
    var input : string
var mark : int
loop
    loop
        put "Please enter a mark"
        get input : *
        exit when strintok (input)
        put "Please enter a valid integer"
    end loop
    mark := strint (input)
    exit when mark > -1 and mark < 101
    put "Stay in range 0 - 100"
end loop

    1.  Since b is used to index the array, if it is not in the range 1 - 5 it will crash the program. If the input for either b or c is not an integer it will crash the program.
    2.  
      var a : array 1 .. 5 of int := init(1, 2, 3, 4, 5)
var b, c : int

loop
    put "Which element do you want to change?"
    get b
    exit when b >= 1 and b <= 5
    put "The index must be in the range 1 - 5"
end loop
put "What value do you want to change it to?"
get c
a(b) := c
    3.  
      var a : array 1 .. 5 of int := init(1, 2, 3, 4, 5)
var b, c : int
var input : string

loop
    loop
        put "Which element do you want to change?"
        get input : *
        exit when strintok (input)
        put "Please enter a valid integer"
    end loop
    b := strint (input)
    exit when b >= 1 and b <= 5
    put "Stay in range 1 - 5"
end loop

loop
    put "What value do you want to change it to?"
    get input : *
    exit when strintok (input)
    put "Please enter a valid integer"
end loop
c := strint (input)
a(b) := c

  5. There are many examples. As computers are being embedded in more devices, the potential for problems increases. The consequences of software bugs can become life threatening, when they control things like airplanes and medical equipment.