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cfunctionstructbsearch

bsearch() comparing by name


I have a struct employee comparators and main:

#define MAX_SIZE 20
typedef struct Employee{
    char name[MAX_SIZE];
    int salary;
    int experience;
} employee_t;

void main()
{
    int i;

    employee_t** employeeArray = (employee_t**)malloc(sizeof(employee_t*)*5);
    employee_t nonExstingEmployee = {"v"};

    for(i=0 ; i < 2 ; i++)
    {
        employeeArray[i] = (employee_t*)malloc(sizeof(employee_t));  //alocate each employee
        readEmployee( employeeArray[i] ); 
    }

    puts("beforesort\n");

    for(i=0; i <2 ; i++)
    {
        printEmployee(employeeArray[i]);
    }

    puts("after salary sort\n");
    qsort(employeeArray, 2, sizeof(employee_t*), compareEmployeesBySalary);
    for(i=0; i < 2 ; i++)
        printEmployee( employeeArray[i] );

    if (bsearch(&nonExstingEmployee, employeeArray, MAX_SIZE, sizeof(employee_t), compareEmployeesByName) == 0)
        puts("employee found");
    else
        puts("no employee found");

}


    int compareEmployeesBySalary(const void* a, const void* b){
            employee_t* one = *(employee_t **)a;
            employee_t* two = *(employee_t **)b;

            if (one->salary == two->salary)
                return 0;
            else if (one->salary > two->salary)
                return 1;
            else
                return -1;
    }

    int compareEmployeesByName(const void* a,const void* b)
    {
        employee_t* one = *(employee_t**)a;
        employee_t* two = *(employee_t**)b;

        if(strcmp(&one->name, &two->name) == 0)
        {
            return 1;
        }

        return 0;
    }

I need to use bsearch comparing the names (with some employee that does not exist in the array), my qsort function works(comparing by salary) no matter how I initialize the employee for bsearch it always says its not there (I'm trying to test this with existing employee first),

How should I initialise my employee (or what should I change?)


[update from comment:]

This is my readEmployee():

void readEmployee(employee_t *emp)
{
  fflush(stdin);
  printf("Please enter Employee's name:(max 19 chars)");
  scanf("%s", emp->name);

  fflush(stdin);
  printf("Please enter Employee's salary:");
  scanf("%d", &(emp->salary));

  fflush(stdin);
  printf("Please enter Employee's experience:");
  scanf("%d", &(emp->experience));
}

I'm comparing the nonExstingEmployee (which exist in the array for testing) and my employeeArray.


Solution

  • How should I initialise my employee

    You might want to show us how you do it (readEmployee()?), and we would comment on this.

    (or what should I change?)

    Two issues:

    1. The array to be searched is not MAX_SIZE long, but 2.

      So this line

      if (bsearch(&nonExstingEmployee, employeeArray, MAX_SIZE, sizeof(employee_t), compareEmployeesByName) == 0)
      

      should be

      if (bsearch(&nonExstingEmployee, employeeArray, 2, sizeof(employee_t), compareEmployeesByName) == 0)
      
    2. In compareEmployeesByName() you pass the "wrong" address.

      This line

      if(strcmp(&one->name, &two->name) == 0)
      

      should be

      if(strcmp(one->name, two->name) == 0)