How to interpret this line? (struct list*)0)

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while (variavel != (struct lista*)0) {
   ...
}

How to interpret (struct lista*)0)? What does that mean?

c struct cast

1 answer

4


(struct lista*) is a cast, then the code is telling the compiler to interpret the value below as being of this specified type, i.e., a pointer to a structure called lista previously declared. In this case it is only a way to make it clear that you know you are doing it and that is exactly what you want, ie the variable variavel must be exactly the type struct lista *, since 0 originally is a type int, with the cast is guaranteed to be compatible from the point of view of type. But of course, nothing guarantees that the data is what is expected there. The 0 in this case is a null pointer indicator, then the loop will stop when the value of variavel is void.

  • How would the cast look without the pointer? Example: struct variable list. Thanks for the clarifications.

  • 1

    Simple as that just takes the pointer out, but it doesn’t mean it will work in all cases.

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