CPT lab05-02 อันที่ถูก

//main.c
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
struct employee {
  char name[128];
  float salary;
};
typedef struct employee Employee;
float total_salary(Employee a[], int len);
int main() {
    int num,i=0,j=0;
    Employee *all;
    FILE *fp;
    printf("Enter num: ");
    scanf("%d",&num);
    all=(Employee *)malloc(num*sizeof(Employee));

    printf("\nInput---------\n");
    fp=fopen("employee.bin","w+");
    while(i<num){ fflush(stdin);
        printf("[%d]name : ",i+1);
        gets((all+i)->name);
        printf("[%d]salary : ",i+1);
        scanf("%f",&(all+i)->salary);
        fwrite(&all,sizeof(Employee),1,fp);
        i++;
    }
    fclose(fp);

    fp=fopen("employee.bin","r+");
    printf("\nRead---------\n");
    fread(&all,sizeof(Employee),1,fp);
    for(i=0; i<num; i++){
        printf("%s:%.2f\n",(all+i)->name,(all+i)->salary);
    }
    fclose(fp);

    printf("\nTotal Salary = %.1f\n", total_salary(all, num));
    free(all);


    fclose(fp);
    return 0;
}



float total_salary(Employee a[], int len){
    int i;
    float sum=0;
    for(i=0; i<len; i++)
    sum+=(a+i)->salary;
    return sum;
}