CODEWITHSUNDEEP
cstructdynamic-memory-allocation
bdd0
bdd0

Reputation: 91

remove data from structure array

I have a structure to store information of employees

struct employeeData
{
   char name[50];
   int age;
   char rank[50];
   char level[50];
   char memo[100];
 };

I save them into employeeDataArr[size] using malloc in my enterNew function.

Now, I am trying to remove certain employees from the employeeDataArr[size] using their name.

So, I used nameIndex function to see if the inputted named employee exists in the data base. Once the person exist, I am trying to use

free(employeeDataArr[size]);

to remove the information of a certain employee.

I expected to remove their name, age, rank, level and memo for that certain employees. However, It seems like it only removes the name of the employees.

 void removeRecord (struct employeeData * dataBase[])   
    {
      printf("enter employee name");
      int nameIndex
      char employeeName[50];
      scanf(%s, employeeName)
      if(check if the name exists in the data base)
      {
        printf("Error, no such person exists");
      }
      else
      {
        nameIndex = nameIndex(employeeName,dataBase);// search the index of inputted person's data in the dataBase array
        free(dataBase[nameIndex]);//free the memory of inputted person's data from the data base(this only removes the name of the person's data)
    }

When I do this, it gives me like this.

before removal
Name: Test 1
Age: 43
Rank: supervisor
level: 2I
memo: testMemo
After removal
Name:
Age: 43
Rank: supervisor
level: 2I
memo: testMemo

As you can see, only the name data from the actual structure. I thought free would free the memory that i allocated previously which will remove all data of the structure.

It seems like I am not using the free in the way it should. What would be the issue here?

Thank you for your time

Upvotes: 0

Views: 537

Answers (2)

Aleksej
Aleksej

Reputation: 59

Yes. You can set after free() the pointer to NULL. Than it is a little bit clearer. You can also check the allocated memory bevor and after free() .

Upvotes: 1

Denis Glazkov
Denis Glazkov

Reputation: 71

free method in C just tells the operating system that it can now use this piece of memory, this does not mean that the data will actually be deleted.

Upvotes: 1

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