Equivalent using for-loop instead do-while-loop

c for-loop do-while
deathshot picture deathshot · Dec 23, 2013 · Viewed 7.7k times · Source

I was wondering instead of using a do-while loop, what is the equivalent for-loop or any other combination of loops in c?

Answer

Sergey Kalinichenko picture Sergey Kalinichenko · Dec 23, 2013

Any sort of a loop can be constructed from a combination of an infinite "forever" loop, and a conditional break statement.

For example, to convert

do {
    <action>
} while (<condition>);

to a for loop, you can do this:

for (;;) {
    <action>
    if (!<condition>) break;
}

You can use the same trick to convert a do/while loop to a while loop, like this:

while (true) {
    <action>
    if (!<condition>) break;
}

Moreover, the loop is not needed at all: any of the above can be modeled with a label at the top and a goto at the bottom; that is a common way of doing loops in assembly languages. The only reason the three looping constructs were introduced into the language in the first place was to make the language more expressive: the do/while loop conducts author's idea much better than any of the alternatives shown above.

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