[Tutor] coin toss program without using the for/range loop

[Luke Paireepinart]

Kent Johnson wrote:
> David wrote:
>   
>> How to write the coin toss program without using the for/range loop program.
>>
>> Program flips a coin 100 times and then tells you the number of heads 
>> and tails.
>>
>>  
>>
>> I can only solve it using the for/range loop
>>
>>  
>>
>> Import random
>>
>>   Heads=0
>>
>>   For 1 in range (100):
>>
>>   Heads+=random.randrange(2)
>>
>>  
>>
>> print “Hit heads”+” “+str(heads)+” “+”times”+” “ + “hit tails” + “ 
>> “+str(100-heads)+” “ + “times”
>>
>>  
>>
>> I don’t see how you solve this program just using the while loop program 
>> and if/else statement.
>>     
>
> This sounds a lot like homework so I won't give you the whole answer, 
> but you can write a for loop using while and a counter variable.
>
>   
In fact, in most languages a for loop and a while loop are very similar:

for(int i =0; i < 100; i++)
{
    //do something
}
is the same as
int i = 0
while (i < 100)
{
    // do something
    i++;
}

The difference in Python comes from the fact that the 'for' loop 
iterates over a list of objects,
rather than incrementing a variable.
If you're using a for-range loop in Python you're using it in the 
old-style that C and C++ programs use (other languages too)
in which case you could easily use a while loop as well.
But if you're indexing into a specific list,
it becomes much more clear why we use python's 'for',
to index directly into that list without having to deal with an index 
variable.

for x in some_list:
    // do something with x

rather than

index = 0
while index < len(some_list):
    x = some_list[index]
    // do something with x
    index += 1

HTH,
-Luke
> Kent
>
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