Display the biggest cylinder capacity of all the cars in C — structures - c

Question

#include <stdio.h>
#include <conio.h>
#include <string.h>
#include <stdlib.h>
typedef struct {
char model[50], mark[50], color[50];
int cylinderCap;
} car;
void read(car *cr, int *nr) {
printf("Insert mark: ");
(*nr)++;
fflush(stdin);
gets((cr + *nr)->mark);
printf("Insert model: ");
gets((cr + *nr)->model);
printf("Insert color: ");
gets((cr + *nr)->color);
printf("Insert the cylinder capacity: ");
scanf("%d", &((cr + *nr)->cylinderCap));
}
void display(car *cr, int nr) {
printf("\n%-10s \t%-10s \t%-10s %d", (cr + nr)->mark, (cr + nr)->model,
(cr + nr)->color, cr[nr].cylinderCap);
}
void search_model(car *cr, int *nr, char mod[50]) {
int i;
for(i = 0; i <= (*nr); i++)
if(strcmp((cr + i)->model, mod) == 0)
display(cr, i);
}
void search_cc(car *cr, int *nr, int cc) {
int i;
for(i = 0; i <= (*nr); i++)
if((cr + i)->cylinderCap >= cc)
display(cr, i);
}
void clear(car *cr, int *nr, char mod[50]) {
int k = 0,i,j;
for(i = 0; i <= (*nr); i++)
if(strcmp((cr + i)->model, mod) == 0)
{
k++;
for(j = i; j <= (*nr - k); j++)
*(cr + j) = cr[j + 1];
}
*nr = *nr - k;
}
void main() {
car cr[50];
int opt, n = -1, i, cc = 1900;
char mod[50];
do{
system("CLS");
printf("1.Add a car\n");
printf("2.Display cars\n");
printf("3.Search a car after its model\n");
printf("4.Display all the cars with cc > 1900\n");
printf("5.Remove a car after its model\n");
printf("6.Exit\n");
printf("7.Display the biggest cyclinder capacity of all the cars\n");
printf("Insert option: ");
scanf("%d", &opt);
switch(opt) {
case 1:
read(&cr[0], &n);
break;
case 2:
printf("\n%-10s \t%-10s \t%-10s %s", "mark", "Model", "color", "Capacity");
for(i = 0; i <= n; i++)
display(cr, i);
break;
case 3:
printf("Insert model: ");
scanf("%s", mod);
printf("\n%-10s \t%-10s \t%-10s %s", "mark", "Model", "color", "Capacity");
search_model(&cr[0], &n, mod);
break;
case 4:
printf("\n%-10s \t%-10s \t%-10s %s", "mark", "Model", "color", "Capacity");
search_cc(&cr[0], &n, cc);
break;
case 5:
printf("Insert the model you wish to delete: ");
scanf("%s", mod);
clear(&cr[0], &n, mod);
break;
case 6:
break;
case 7:
break;
default: printf("Error! Please try another option!\n");
break;
}
getch();
}while(opt != 6);
getch();
}
This will display:
1.Add a car
2.Display cars
3.Search a car after its model
4.Display all the cars with cc > 1900
5.Remove a car after its model
6.Exit
7.Display the biggest cylinder capacity of all the cars
Insert option:
I don't have any idea how to do the last one, I don't even know how to begin!
I tried something like this, but with no success:
void maximum(car *cr, int *nr, int max) {
int i;
for(i = 0; i <- (*nr); i++)
if(((cr + i)->car) >=max))
max = (cr + i)->car;
display(max);
}
But it doesn't really work, so any help would be appreciated!

Answer 1

Your maximum function doesn't make any sense. You're trying to use an object type as an item for a struct, using superfluous pointer arithmetic and other things that were already discussed in the comments in your post.
void maximum(car *cr, int nr)
{
int i, max = 0;
for(i = 1; i <= nr - 1; i++)
{
if(cr[i].cilinderCap >= cr[max].cilinderCap)
{
max = i;
}
}
display(cr, max);
}
Note: try to understand my code before copying it to your file.
This is the most intuitive approach one can get. Note I'm using the "cylinder capacity" variable to actually check, uhm, the maximum cylinder capacity.
Also note that if you start your cars at index 0, you should search up to n - 1, and not n. The referenced parameter for nr is also redundant, as you don't even try to modify it.
So, you just call:
maximum(cr, n);
Another thing is that you should check for errors in the function, as in its current state, it might crash if there are no elements in the list.
There are some other "ethically incorrect stuff" in your code that are irrelevant to the question, but I recommend reading some articles on Google about struct lists.