getting bubble sort to work with structure - c

Question

im not sure how to bubble sort using structures, id like the function sortMovies to be able to sort the movies alphebeticaly by title but i am getting these errors listed below.
#include <stdio.h>
#include <conio.h>
#define CONST 100
void sortMovies(struct movies main[CONST]);
void changeMovie(struct movies main);
int findMovie(struct movies main, int nOfMovies, struct movies tempMovie);
struct movies newMovie();
typedef struct movies{
char title[30];
char UPC[12];
int qnty;
double price;
}movies;
int main()
{
int nOfMovies = 0, findR, stop = 0, nOfMoviesArr[CONST];
char decider;
while (stop != 1)
{
movies main[CONST];
movies tempMovie;
printf("(A)dd a new movie\n(C)hange a Movie's Information \n(D)elete a Movie \n(L)ist All Movies\n(Q)uit");
scanf(" %c", &decider);
switch (decider)
{
case 'a':
case 'A':
tempMovie = newMovie();
nOfMovies = findMovie(main[CONST], nOfMovies, tempMovie);
nOfMovies++;
break;
case 'c':
case 'C':
printf("enter movie upc:");
scanf("%s", main);
break;
case 'l':
case 'L':
sortMovies(main[CONST]);
break;
case 'q':
case 'Q':
return 0;
break;
default:
printf("An invalid option was selected!");
}
}
}
struct movies newMovie() {
movies new;
printf("enter movie upc:");
scanf("%s", new.UPC);
printf("enter movie title:");
scanf("%s", new.title);
printf("enter movie qauntity:");
scanf("%d", new.qnty);
if (new.qnty <= 0)
{
printf("quanitity must be greater than 0");
printf("enter movie qauntity:");
scanf("%d", new.qnty);
}
printf("enter movie price:");
scanf("%lf", new.price);
if (new.price <= 0)
{
printf("price must be greater than 0");
printf("enter movie price:");
scanf("%lf", new.price);
}
return new;
}
int findMovie(struct movies main, int nOfMovies, struct movies tempMovie)
{
int count;
for (count = 0; count < nOfMovies; count++)
{
if (tempMovie.UPC == main.UPC)
{
return count;
}
else
{
printf("error");
return -1;
}
}
}
void changeMovie(struct movies main)
{
char decider;
printf("would you like to change the value? y or no input");
switch (decider)
{
case 'y':
case 'Y':
printf("enter movie title:");
scanf("%c", main.title);
printf("enter movie qauntity:");
scanf("%d", main.qnty);
if (main.qnty <= 0)
{
printf("quanitity must be greater than 0");
printf("enter movie qauntity:");
scanf("%d", main.qnty);
}
printf("enter movie price:");
scanf("%lf", main.price);
if (main.price <= 0)
{
printf("price must be greater than 0");
printf("enter movie price:");
scanf("%lf", main.price);
}
break;
return 0;
}
}
void sortMovies(struct movies main[CONST])
{
int i, sflag, count = 0;
char temp;
do
{
sflag = 0;
for (i = 1; i < CONST; i++)
{
if (main[i - 1].title > main[i].title)
{
temp = main[i - 1].title;
main[i - 1].title = main[i].title;
main[i].title = temp;
sflag = 1;
}
}
count++;
} while (sflag);
for (i = 0; i < CONST; i++)
{
printf("%c\t%c\t%d\t%lf", main[i].title, main[i].UPC, main[i].qnty, main[i].price);
}
} ```
Severity Code Description Project File Line Suppression State Suppression State
Error C2440 'function': cannot convert from 'movies' to 'movies *' 40
Error (active) E0167 argument of type "movies" is incompatible with parameter of type "struct movies *" 40
Error (active) E0137 expression must be a modifiable lvalue 148
Error C2106 '=': left operand must be l-value 148
Error (active) E0137 expression must be a modifiable lvalue 149
Error C2106 '=': left operand must be l-value 149

Answer 1

Error (active) E0167 argument of type "movies" is incompatible with parameter of type "struct movies *" 40
This is happening because with main[CONST] you are trying to pass a single element of of the main array (the element at index CONST), rather than the whole array when the sortMovies method expects an array. To pass the whole array into the function, use sortMovies(main);.
Error (active) E0137 expression must be a modifiable lvalue 148
Error C2106 '=': left operand must be l-value 148
Error (active) E0137 expression must be a modifiable lvalue 149
Error C2106 '=': left operand must be l-value 149
This is happening because you are trying to copy the contents of one char array to another with the = operator, which is not valid. Instead, use strcpy(main[i - 1].title, main[i].title) and strcpy(main[i].title, temp).
Also, in your sortMovies function you declare temp as a char which you try to use to swap the title strings. What you want here is instead char* temp. If you are not familiar with this syntax, I would recommend reading up on pointers in C. They are a very important construct in the language, and a better understanding of pointers will likely also help you clear up a lot of the issues you are having with this program.