need help with this question

[csci1123]

double fun(double *x); // code given somewhere else

void main ()
{
double a [ ] {3.0, 1.0, 4.0, 1.0, 5.0};
double b = fun (a);
. . .

a) Is this (partial) code syntactically correct?
b) What piece of information does the code in "fun" have to obtain from another source?

[BobMorane]

a) Is this (partial) code syntactically correct?

Yeah, if you add at minimum:

return 0;
}

after the declaration of b.

b) What piece of information does the code in "fun" have to obtain from another source?

What do you mean by "another source"?

[mbozzi]

It is not syntactically correct, but maybe not why you expect.
The C++ standard says that programs' main function shall (must) return int.

3.6.1 Main function [basic.start.main]
An implementation shall not predefine the main function. This function shall not be overloaded. It shall have a return type of type int, but otherwise its type is implementation defined. All implementations shall allow both of the following definitions of main:
int main() { /* ... */ }
and
int main(int argc, char* argv[]) { /* ... */ }

In other words: void main() is wrong.

BobMorane wrote:

Yeah, if you add at a minimum:

return 0;
}

after the declaration of b

Unique among all functions returning non-void, C++'s main function does not require a return statement.

3.6.1 Main function [basic.start.main]
If control reaches the end of main without encountering a return statement, the effect is that of executing return 0;

[BobMorane]

Unique among all functions returning non-void, C++'s main function does not require a return statement.

Wow, I did not know that! Thanks.

[1vRz3TCk]

b) What piece of information does the code in "fun" have to obtain from another source?

Hint: double b = fun (a); a is an array.