Friday Finking: Contorted loops

[Alan Gauld]

On 11/09/2021 15:41, Peter J. Holzer wrote:

> How is C's do/while loop more horrible than Pascal's repeat/until? 

Because it is very hard to spot or distinguish from a normal
while loop.

while condition ;

Is a valid (and fairly common) loop in C

so code that has

do{
code
}
while condition;

Looks, for non-trivial cases, like a lot of code followed
by an empty while loop.

The do is easy to miss  and the while loop disguised as
a repeat termination is confusing.

repeat
code
until condition

Is far clearer to comprehend since there is no ambiguity.

> In an old collection of small C programs of mine I find:
> 
> 35 regular for loops
> 28 while loops
> 2 infinite for loops
> 1 "infinite" for loop (i.e. it exits somewhere in the middle)
> 0 do/while loops.

That wouldn't surprise me, I've only used do/while in C
a handful of times. But in Pascal I use it regularly.

-- 
Alan G
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