I'm using a function to create a dynamic array using MALLOC.

getting user input with the use of SCANF. for some reason I get this Error statement:

** Unhandled exception at 0x00007FFEE518D646 (ucrtbased.dll) in Project4STRUCTS.exe: 0xC0000005: Access violation writing location 0xFFFFFFFFCD7AE350.**

THE CODE

THE PROBLEM IS IN THE FUNCTION CALLED INPUT_DATA

#define _CRT_SECURE_NO_WARNINGS

#define SIZE 3

#include<stdio.h>

typedef struct student_init_data {
    
    int ID;
    int* StudentGradeArray;
    int NumOfExams;

}Student_init_data;

typedef struct student_processed_data {
    
    int ID;
    int StudentAvg;

    
}Student_processed_data;

typedef struct statistics {

    Student_processed_data* HIGH;
    Student_processed_data* LOW;
    int SizeofHIGH;
    int SizeofLOW;
    int Tavg;


}Statistics;


int* Input_Data(int Exams) {

    int i;
    int* arr = (int*)malloc(Exams * sizeof(int));

    for (i = 0;i < Exams;i  )
    {
        printf("enter Grade: ");
        scanf("%d", &arr[i]);

    }

    return arr;


}

int Student_Average(int* GradeArray,int NumofExams) {

    int i;
    int avg=0;
    for (i = 0;i < NumofExams;i  )
        avg = avg   GradeArray[i];
    avg = avg / NumofExams;
    return avg;

}

int Total_Average(Student_processed_data StudentAVG[SIZE], int NumofStudents) {

    int i;
    int avg = 0;
    for (i = 0;i < NumofStudents;i  )
        avg = avg   StudentAVG[i].StudentAvg;
    avg = avg / NumofStudents;
    return avg;

}


void Classification(Student_init_data InitStudentData[SIZE],Statistics *pStats) {

    int i;
    Student_processed_data StudentAVG[SIZE];

    pStats->SizeofHIGH = 0;
    pStats->SizeofLOW = 0;


    for (i = 0;i < SIZE;i  )
        StudentAVG[i].ID = InitStudentData[i].ID;


    for (i = 0;i < SIZE;i  )
    {
        StudentAVG[i].StudentAvg = Student_Average(InitStudentData[i].StudentGradeArray, InitStudentData[i].NumOfExams);
    }

    pStats->Tavg = Total_Average(StudentAVG, SIZE);


    for (i = 0;i < SIZE;i  )
    {
        if (StudentAVG[i].StudentAvg >= pStats->Tavg)
            (pStats->SizeofHIGH)  ;
        else
            (pStats->SizeofLOW)  ;


    }


    pStats->HIGH = (Student_processed_data*)malloc((pStats->SizeofHIGH) * sizeof(Student_processed_data));
    pStats->LOW = (Student_processed_data*)malloc((pStats->SizeofLOW) * sizeof(Student_processed_data));



    for (i = 0;i < SIZE;i  )
    {

        if (StudentAVG[i].StudentAvg >= pStats->Tavg)
            (pStats->HIGH)[i] = StudentAVG[i];// High=pointer||same as High[i]
        else
            (pStats->LOW)[i] = StudentAVG[i];// HIGH={ID,AVG}, StudentAVG={ID,AVG}
    }



}

void Print_Tab(Statistics Stats) {

    int i;
    printf("Total Average is:%d ", Stats.Tavg);
    printf("\n %d number of students had AVG higher than TAVG:\n", Stats.SizeofHIGH);
    
    for (i = 0;i < Stats.SizeofHIGH;i  )
    {
        printf("ID:%d , AVG:%d | ", (Stats.HIGH)[i].ID, (Stats.HIGH)[i].StudentAvg);
    }
    printf("\n %d number of students had AVG lower than TAVG:\n", Stats.SizeofLOW);

    for (i = 0;i < Stats.SizeofLOW;i  )
    {
        printf("ID:%d , AVG:%d | ", (Stats.LOW)[i].ID, (Stats.LOW)[i].StudentAvg);
    }


}

void Free_Mem(Statistics* Pfreestat, Student_init_data* PfreeStudentData) {

    
    free(Pfreestat->LOW);
    free(PfreeStudentData->StudentGradeArray);
    free(Pfreestat->HIGH);
}

void main() {

    int i;
    Student_init_data StudentData[SIZE];
    Statistics Stats;
    

    for (i = 0;i < SIZE;i  )
    {
        printf("\nEnter Stundent Num %d ID and Number of Exams:\n", i   1);
        scanf("%d", &StudentData[i].ID);
        scanf("%d", &StudentData[i].NumOfExams);
        StudentData[i].StudentGradeArray = Input_Data(StudentData[i].NumOfExams);

    }



    Classification(StudentData ,&Stats);
    Print_Tab(Stats);
    Free_Mem(&Stats,&StudentData);




    

}

ERROR MESSAGE

Thank you all, Eyal

I tried debugging to see the problem, and couldn't get more than the understanding that the problem falls with the SCANF.

I tried looking into this certain exception online, couldn't find something with the same issue.

CodePudding user response：

Some problems:

1. You should include #include <stdlib.h> for the memory management functions.
2. Change Free_Mem(&Stats,&StudentData); to Free_Mem(&Stats,StudentData); because StudentData is an array of structs.
3. Change free(PfreeStudentData->StudentGradeArray); to for (int i = 0; i < SIZE; i ) free(PfreeStudentData[i].StudentGradeArray);
4. void main() is non-standard C. Better to use int main() and return 0 at completion.

Try with these changes.