parking.c

#include<stdio.h>
#include<stdlib.h>

struct Car{
    int id;
    int count;
    struct Car *next; 
};


 /**
  *  @return
  */

int car_in(struct Car *p, int type);


 /**
  *  @return
  */
  
int car_out(struct Car *p, int type);


 /**
  *  @return 
  */
  
int print_cars(struct Car *p);



int main(void){
    char command;
    int car_id,r=1;
    struct Car *root=NULL, *tmp;
    while(1){
        printf("COMMAND:");
        scanf(" %c",&command);
        switch(command){
            case 'i':
                printf("CAR_TYPE:");
                scanf("%d",&car_id);
                if(root==NULL){
                    root = (struct Car *)calloc(1,sizeof(struct Car));
                    if(root==NULL){
                        r=-1;
                    }else{
                        root->id=car_id;
                        root->count=1;
                        root->next=NULL;
                        r=1;
                    }
                }else{
                    r=car_in(root,car_id);
                }
                break;
            case 'o':
                printf("CAR_TYPE:");
                scanf("%d",&car_id);
                if(root->id == car_id){
                    root->count--;
                    if(root->count == 0){
                        tmp=root;
                        root=root->next;
                        free(tmp);
                    }else if(root->count < 0){
                        r=-2;
                    }else{
                        r=1;
                    }
                }else{
                    r=car_out(root,car_id);
                }
                break;
            case 'p':
                if(root==NULL){
                    printf("NO Cars\n");
                    r=1;
                    break;
                }
                r=print_cars(root);
                break;
            case 'e':
                r=0;
                break;
            case 'h':
            default:
                printf("----Command List-----\n");
                printf(" i  | insert car\n");
                printf(" o  | out car \n");
                printf(" p  | print car list\n");
                printf(" e  | exit \n");
                printf(" h  | show help\n");
                r=1;
        }
        if(r==-1){
            printf("error:car_in\n");
        }else if(r==-2){
            printf("error:car_out\n");
        }else if(r==-3){
            printf("error:print_cars\n");
        }else if(r==0){
            printf("exit\n");
            break;
        }
    }
    return 0;
}



int car_in(struct Car *p, int type){
    while(1){
        if(p->id == type){
            p->count += 1;
            return 1;
        }else{
            if(p->next == NULL){
                p->next = (struct Car *)malloc(sizeof(struct Car));
                if(p->next == NULL) return -1;
                p->next->id = type;
                p->next->count = 1;
                p->next->next = NULL;
                return 1;
            }
            p = p->next;
        }
    }
}


int car_out(struct Car *p, int type){
    struct Car *tmp;
    while(1){
        if(p->next->id == type){
            p->next->count -= 1;
            if(p->next->count == 0){
                tmp = p->next;
                p->next = p->next->next;
                free(tmp);
            }
            return 1;
        }
        if(p->next->next == NULL) return -2;
        p = p->next;
    }
}


int print_cars(struct Car *p){
    while(1){
        printf("ID : %d\n", p->id);
        printf("COUNT : %d\n", p->count);
        if(p->next == NULL) return 1;
        p = p->next;
    }
    return -3;
}