如何从函数传递结构和int并返回给main？ C

Question

I am trying to return back the array persons and the quantity_persons_count to main() but I cant get it to work. I have tried changing void to int and person but that obv doesnt work.

struct person{..}
int main(){
 int o;
 int quantity_persons_count = 0;
 struct person persons[100];

 while(1){

    printf("1.Add a new person");
    scanf("%i",&o);

    switch(o)
    {
        case 1: AddPerson(persons,quantity_persons_count);
                break;
}

void AddPerson(struct person *persons, int quantity_persons_count){
 if(quantity_persons_count == 100){
    printf("ERROR.\n");
 }
 else{
     printf("name\n");
     scanf("%s",persons[quantity_persons_count+1].name);
     quantity_persons_count++;
     printf("done\n");

}

}

Answer 1

If you want changes to quantity_persons_count to be visible in main , you need to pass a pointer to it:

void AddPerson(struct person *persons, int *quantity_persons_count){

     if(*quantity_persons_count == 100){
        printf("ERROR.\n");
     }
     else{
         printf("name\n");
         scanf("%s",persons[*quantity_persons_count+1].name);
         (*quantity_persons_count)++;
         printf("done\n");

    }

}

Then you call it like this:

AddPerson(persons,&quantity_persons_count);