macOS Another frustrating error in C

[Quboid]

Hello all,
I've probably posted over 10 programing questions here already and i don't think this would be the last one, so before i start let me just thank you guys (and girls) for being so helpful, I think you are an exceptionally resourcefull bunch of internet freinds.

Now, I am trying to practice structure in c, So I am writing a program that is suppose to capture the vocals and their corresponding ascii in a list-structure.
I wrote the code to capture the data but now i am trying to print it on the screen and it i am getting a strange error( to me atleast) that says that i am missing a ")" in a while statement. I'll post hte code so you guys( and girls) can take a look. Thanks in advance for the help.

#include<stdio.h>


#define null 0;
// Prototypes

void menu();
void insert();
void fill();
void mostrar();
void delete_data();

// LIST DeClArAtIoN

struct lista{
char vocal;
int ascii;
struct lista *liga;
};

struct lista *inicio,*nodo,*fin,*aux;
char voc; int ascii;
char respuesta;









void main()
{
menu();
getch();

}

void menu()
{ int option;
do{
printf("\n\t\t ####**** MENU ****####");
printf("\n\n\t1. Insert data from the begining of the list");
printf("\n\n\t2. insert data from the end of the list");
printf("\n\n\t3. Show Data on screen");
printf("\n\n\t4. Delete data");
printf("\n\n\t5. exit");
scanf("%i",&option);
if(option==1)
{
insert();
}
if(option==2)
{
fill();
}
if(option==3)
{
mostrar();
}




}while(option!=5);
}



void insert()
{
struct lista *inicio,*nodo,*fin;
char voc; int ascii;
char respuesta;

inicio=(struct lista*)malloc(sizeof(struct lista));
printf("\n\t introduce el voval\t");
fflush(stdin);
scanf("%c",&voc);
(*inicio).vocal=voc;
printf("\n\t Introduce el ascii para %c\t",voc);
fflush(stdin);
scanf("%i",&ascii);
(*inicio).ascii=ascii;
fin=inicio;
(*inicio).liga=null;

do{
nodo=(struct lista*)malloc(sizeof(struct lista));
printf("\n\tIntroduce vocal\t");
fflush(stdin);
scanf("%c",&voc);
(*nodo).vocal=voc;
printf("\n\t Introduce el ascii\t");
fflush(stdin);
scanf("%i",&ascii);
(*nodo).ascii=ascii;
(*nodo).liga=inicio;
inicio=nodo;
printf("\n\t Quieres continuar? si(s)/no(n)\t");
fflush(stdin);
scanf("%c",&respuesta);
}while(respuesta!='n');
}



void fill()
{

inicio=(struct lista*)malloc(sizeof(struct lista));
printf("\n\t Give me a vowel\t");
fflush(stdin);
scanf("%c",&voc);
printf("\n\t Give me the ascii for %c",voc);
fflush(stdin);
scanf("%i",&ascii);
(*inicio).ascii=ascii;
(*inicio).vocal=voc;
(*inicio).liga=null;
fin=inicio;

do{
nodo=(struct lista*)malloc(sizeof(struct lista));
printf("\n\t Give me another vowel");
fflush(stdin);
scanf("%c",&voc);
printf("\n\t Give me the ascii for %c", voc);
fflush(stdin);
scanf("%i",&ascii);
(*nodo).vocal=voc;
(*nodo).ascii=ascii;
(*nodo).liga=null;
(*fin).liga=null;
fin=nodo;
printf("\n\t Do you want to continue? yes(y), no(n)");
fflush(stdin);
scanf("%c",&respuesta);
}while(respuesta!='n');
}

void mostrar()
{
aux=inicio;
while(aux!=null){
printf("\n\n\t %c",(*aux).vocal);
printf("\n\n\t %i",(*aux).ascii);
aux=(*aux).liga;
};
}

 

[Doctor Q]

The problem is that you shouldn't have the semicolon here:

#define null 0;

The define directive doesn't use a trailing semicolon, so it treats that as one of the tokens in your definition. You are defining "null" to mean a zero and a semicolon, when you only want it to be a zero.

Your line

while( aux!=null ){

was being interpreted as

while( aux!= 0; ){

which generated the error.

* * *

Also, you should not use a trailing semicolon in this syntactic form

while(a==b) { ... };

because the closing brace is enough. That extra semicolon creates an empty statement, equivalent to this:

while(a==b) { ... }
/* statement that does nothing */ ;

Normally, an empty statement is harmless, but it would break code like this:

if (c==d) while(a==b) { ... }; else ... ;

 

[caveman_uk]

Whilst we're on the subject never do

for (...);

as the semicolon makes the for loop do nothing.

 

[Doctor Q]

Whilst we're on the subject never do

for (...);

as the semicolon makes the for loop do nothing.

Good advice. But there's an exception: cases where side effects are the goal. Here's code, for example, to find the end of a string:

for ( mypointer = mystring ; *mypointer != '\0' ; mypointer++ ) ;

Because extraneous semicolons can so easily lead to errors, I've established a habit that I always observe: If I really do want a null statement, I use braces instead of a semicolon, to make it obvious that it's on purpose. So I'd code my example as follows:

for ( mypointer = mystring ; *mypointer != '\0' ; mypointer++ ) {}