#define _CRT_SECURE_NO_WARNINGS

#include <stdio.h>

#define  SIZE 4

// Declare Struct Employee
struct employee {
	int id;
	int age;
	double salary;
};

/* main program */
int main(void) {
	int l = 0, i = 0, k = 0, j = 0;
	int option = 0;
	int empId;
	double empSalary;
	int empFound = 0;
	printf("---=== EMPLOYEE DATA ===---\n\n");


	struct employee emp[SIZE] = { {0} };
	do {
		printf("1. Display Employee Information\n");
		printf("2. Add Employee\n");
		printf("3. Update Employee Salary\n");
		printf("4. Remove Employee\n");
		printf("0. Exit\n\n");
		printf("Please select from the above options: ");

		scanf("%d", &option);
		printf("\n");

		switch (option) {
		case 0:
			break;
		case 1:
			printf("EMP ID  EMP AGE EMP SALARY\n");
			printf("======  ======= ==========\n");
			for (j = 0; j < i; j++) {
				printf("%6d%9d%11.2lf\n", emp[j].id, emp[j].age, emp[j].salary);
			}
			printf("\n");
			break;
		case 2:
			printf("Adding Employee\n");
			printf("===============\n");
			if (i >= SIZE) {
				printf("ERROR!!! Maximum Number of Employees Reached\n\n");
			}
			else {
				printf("Enter Employee ID: ");
				scanf("%d", &emp[i].id);
				while (emp[i].id < 0) {
					printf("\nPlease input a value higher than 0: ");
					scanf("%d", &emp[i].id);
				}
				printf("Enter Employee Age: ");
				scanf("%d", &emp[i].age);
				printf("Enter Employee Salary: ");
				scanf("%lf", &emp[i].salary);
				printf("\n");
				i++;
			}
			break;
		case 3:
			printf("Update Employee Salary\n");
			printf("======================\n");
			do {
				printf("Enter Employee ID: ");
				scanf("%d", &empId);
				for (k = 0; k < SIZE; k++) {
				if (emp[k].id == empId) {
					printf("The current salary is %0.2lf\n", emp[k].salary);
					printf("Enter Employee New Salary: ");
					scanf("%lf", &empSalary);
					emp[k].salary = empSalary;
					empFound = 1;
					printf("\n");

				}
			}
				if (empFound == 0) {
				printf("*** ERROR: Employee ID not found! ***\n");
			}
			} while (empFound != 1);
			break;
		case 4:
			printf("Remove Employee\n");
			printf("===============\n");
				printf("Enter Employee ID: ");
				scanf("%d", &empId);
				l = 0;
				empFound = 0;
				while (empFound == 0) {
					l++;
					if (empId == emp[l].id) {
						printf("Employee %d will be removed\n\n", empId);
						empFound = 1;
					}
					if (empFound == 0) {
						printf("*** ERROR: Employee ID not found! ***\n");
					}
				}
				for (l = l; l < 4; l++) {
					emp[l].id = emp[l + 1].id;
					emp[l].age = emp[l + 1].age;
					emp[l].salary = emp[l + 1].salary;
				}
				i--;
			} while (empFound != 1);
				break;
		default:
			printf("ERROR: Incorrect Option: Try Again\n\n");
		}
	} while (option != 0);

	printf("Exiting Employee Data Program. Good Bye!!!\n");

	return 0;
}