[SOLVED] A C++ compile time error I do not understand.

AlexBB · 01-03-2015, 07:54 PM

I have this code:

Code:

void main()  {

     printf("\n  Please enter m, n, x and y: "); 
     scanf("%d %d %lf %lf", &M,&N,&X,&Y);     
     printf("  m = %d, n = %d, x = %f, y = %f\n\n", M, N, X, Y);
     CLPMN(M,N,X,Y,CPM,CPD);
     printf("   m   n    Re[Pmn(z)]     Im[Pmn(z)]    Re[Pmn'(z)]    Im[Pmn'(z)]\n");
     printf(" -------------------------------------------------------------------\n");  
     for (J=0; J<=M; J++) {
       printf("   %d   %d  %12.6f   %12.6f   %12.6f   %12.6f\n", 
	          J, N, CPM[J][N][0], CPM[J][N][1], CPD[J][N][0], CPD[J][N][1]);
     }
     printf("\n");
   }

The compilation with g++ gives me a single error:

Quote:

mclpmn.cpp:250:14: error: ‘::main’ must return ‘int’
void main() {
^

At Preview time I noticed that the caret ^ moved to the left border. In actual Terminal in Ubuntu it points to between two parentheses:

Quote:

main()

What kind of integer does the program expect and why?

Sorry for double posting. I don't know how to remove the other one I attached to one of my previous threads. Thanks, - A.

astrogeek · 01-03-2015, 08:48 PM

In c++ main() cannot be void - illegal.

Code:

void main(){...} /* BAD! */

int main(){...} /* GOOD! */

The main() function must return an integer.

The reason is related to the kernel exit() call implicit in exiting main().

I think that some compilers will allow you write a void main(), but it is actually not allowed by the language.

AlexBB · 01-04-2015, 10:00 AM

Thank you, astrogeek. It is not my code. I got it on the web. But I've learned a lesson. -A.

AlexBB · 01-04-2015, 10:28 AM

Just tried it an it COMPILED!!! Such a simple solution! Thanks.