Question

I am having a problem initializing an array of structs. I’m not sure if I am doing it right because I get "initialization from incompatible pointer type" & "assignment from incompatible pointer type". I added in the code where I get these warnings, and when I try to print the data from the struct I just get garbage such as @@###

typedef struct
{
    char* firstName;
    char* lastName;
    int day;
    int month;
    int year;
} student;

// Initialize array

student** students = malloc(sizeof(student));
int x;
for(x = 0; x < numStudents; x++)
{
    // Here I get: "assignment from incompatible pointer type"
    students[x] = (struct student*)malloc(sizeof(student));
}

int arrayIndex = 0;

// Add struct

// Create student struct

// Here I get: "initialization from incompatible pointer type"
student* newStudent = {"john", "smith", 1, 12, 1983};

// Add it to the array
students[arrayIndex] = newStudent;
arrayIndex++;

Answer 1

This is incorrect:

student** students = malloc(sizeof(student));

You do not want a **. You want a * and enough space for how ever many students you need

student *students = malloc(numStudents * sizeof *students); // or sizeof (student)
for (x = 0; x < numStudents; x++)
{
    students[x].firstName = "John"; /* or malloc and strcpy */
    students[x].lastName = "Smith"; /* or malloc and strcpy */
    students[x].day = 1;
    students[x].month = 12;
    students[x].year = 1983;
}

If you still want to use the code in your “//add struct” section, you’ll need to change the line:

student* newStudent = {"john", "smith", 1, 12, 1983};

to

student newStudent = {"john", "smith", 1, 12, 1983};

You were getting “initialization from incompatible pointer type” because you were attempting to initialize a pointer to student with an object of type student.