파일 입출력을 라이브러리 입출력에서 시스템 입출력으로 바꾼 코드입니다.

Question

//*************************************************************** // HEADER FILE USED IN PROJECT //*************************************************************** #include #include #include #include #include #include //*************************************************************** // STURUCTURE USED IN PROJECT //**************************************************************** struct student { int rollno; char name[50]; int p_marks, c_marks; double per; char grade; }st; //*************************************************************** // global declaration //**************************************************************** //수정 //FILE* fptr; int fptr; //*************************************************************** // function to write in file //**************************************************************** void write_student() { errno_t err; //수정 //err = fopen_s(&fptr, "student.dat", "ab"); //return 0 if success fptr = open("student.dat", O_RDWR | O_APPEND); printf(" Please Enter The New Details of student "); printf(" Enter The roll number of student "); scanf_s("%d", &st.rollno); getchar(); // flushing buffer printf(" Enter The Name of student "); gets_s(st.name, sizeof(st.name)); printf(" Enter The marks in physics out of 100 : "); scanf_s("%d", &st.p_marks); printf(" Enter The marks in chemistry out of 100 : "); scanf_s("%d", &st.c_marks); st.per = (st.p_marks + st.c_marks) / 2.0; if (st.per >= 60) st.grade = 'A'; else if (st.per >= 50 && st.per < 60) st.grade = 'B'; else if (st.per >= 33 && st.per < 50) st.grade = 'C'; else st.grade = 'F'; //수정 //fwrite(&st, sizeof(st), 1, fptr); write(fptr, &st, sizeof(st)); //수정 //fclose(fptr); close(fptr); printf(" Student Record Has Been Created. Press any key.... "); _getch(); } //*************************************************************** // function to read all records from file //**************************************************************** void display_all() { //errno_t err; int i; system("cls"); printf(" DISPLAY ALL RECORD !!! "); printf("==================================================== "); printf("R.No. Name P C Ave Grade "); printf("==================================================== "); //수정 //err = fopen_s(&fptr, "student.dat", "rb"); fptr = open("student.dat", O_RDONLY); if (fptr == NULL) return; //수정 //while ((i = fread(&st, sizeof(st), 1, fptr)) > 0) { while ((i = read(fptr, &st, sizeof(st)))) { printf("%-6d %-10s %-3d %-3d %-3.2f %-1c ", st.rollno, st.name, st.p_marks, st.c_marks, st.per, st.grade); } //수정 //fclose(fptr); close(fptr); _getch(); } //*************************************************************** // function to read specific record from file //**************************************************************** void display_sp(int n) { int flag = 0; //errno_t err; //수정 //err = fopen_s(&fptr, "student.dat", "rb"); fptr = open("student.dat", O_RDONLY); if (fptr == NULL) return; //수정 //while ((fread(&st, sizeof(st), 1, fptr)) > 0) { while ((read(fptr, &st, sizeof(st)))) { if (st.rollno == n) { system("cls"); printf(" Roll number of student : %d", st.rollno); printf(" Name of student : %s", st.name); printf(" Marks in Physics : %d", st.p_marks); printf(" Marks in Chemistry : %d", st.c_marks); printf(" Percentage of student is : %.2f", st.per); printf(" Grade of student is : %c", st.grade); flag = 1; } } //수정 //fclose(fptr); close(fptr); if (flag == 0) printf(" record not exist"); _getch(); } //*************************************************************** // function to modify record of file //**************************************************************** void modify_student() { int no, found = 0, i; //errno_t err; system("cls"); printf(" To Modify "); printf(" Please Enter The roll number of student"); scanf_s("%d", &no); //수정 //err = fopen_s(&fptr, "student.dat", "rb+"); fptr = open("student.data", O_WRONLY); if (fptr == NULL) return; //수정 //while ((i = fread(&st, sizeof(st), 1, fptr)) > 0 && found == 0) { while ((i = read(fptr, &st, sizeof(st)) > 0 && found == 0)) { if (st.rollno == no) { printf(" Roll number of student : %d", st.rollno); printf(" Name of student : %s", st.name); printf(" Marks in Physics : %d", st.p_marks); printf(" Marks in Chemistry : %d", st.c_marks); printf(" Percentage of student is : %.2f", st.per); printf(" Grade of student is : %c", st.grade); printf(" Please Enter The New Details of student "); printf(" Enter The roll number of student "); scanf_s("%d", &st.rollno); getchar(); //flushing buffer (fflsh�� ۵��) printf(" Enter The Name of student "); gets_s(st.name, sizeof(st.name)); printf(" Enter The marks in physics out of 100 : "); scanf_s("%d", &st.p_marks); printf(" Enter The marks in chemistry out of 100 : "); scanf_s("%d", &st.c_marks); st.per = (st.p_marks + st.c_marks) / 2.0; if (st.per >= 60) st.grade = 'A'; else if (st.per >= 50 && st.per < 60) st.grade = 'B'; else if (st.per >= 33 && st.per < 50) st.grade = 'C'; else st.grade = 'F'; //수정 //fseek(fptr, -(int)sizeof(st), 1); // SEEK_CUR lseek(fptr, -(int)sizeof(st), SEEK_CUR); //수정 //fwrite(&st, sizeof(st), 1, fptr); write(fptr, &st, sizeof(st)); printf(" Record Updated"); found = 1; break; } } //수정 //fclose(fptr); close(fptr); if (found == 0) printf(" Record Not Found "); _getch(); } //*************************************************************** // function to delete record of file //**************************************************************** void delete_student() { int no; //수정 //FILE* fptr2; int fptr2; //errno_t err; system("cls"); printf(" Delete Record"); printf(" Please Enter The roll number of student You Want To Delete"); scanf_s("%d", &no); //수정 //err = fopen_s(&fptr, "student.dat", "rb"); fptr = open("student.dat", O_RDONLY); if (fptr == NULL) return; //수정 //err = fopen_s(&fptr2, "Temp.dat", "wb"); fptr2 = open("Temp.dat", O_WRONLY); //수정 //rewind(fptr); // move file pointer to 0 lseek(fptr, 0, SEEK_SET); //수정 //while ((fread(&st, sizeof(st), 1, fptr)) > 0) { while ((read(fptr, &st, sizeof(st))) > 0) { if (st.rollno != no) { //수정 //fwrite(&st, sizeof(st), 1, fptr2); write(fptr2, &st, sizeof(st)); } } //수정 //fclose(fptr2); close(fptr2); //fclose(fptr); close(fptr); remove("student.dat"); rename("Temp.dat", "student.dat"); printf(" Record Deleted .."); _getch(); } //*************************************************************** // THE MAIN FUNCTION OF PROGRAM //**************************************************************** void main() { char ch; int num; do { system("cls"); printf(" 1.CREATE STUDENT RECORD"); printf(" 2.DISPLAY ALL STUDENTS RECORDS"); printf(" 3.SEARCH STUDENT RECORD "); printf(" 4.MODIFY STUDENT RECORD"); printf(" 5.DELETE STUDENT RECORD"); printf(" 6.EXIT"); printf(" Please Enter Your Choice (1-6) "); ch = _getche(); switch (ch) { case '1': system("cls"); write_student(); break; case '2': display_all(); break; case '3': system("cls"); printf(" Please Enter The roll number "); scanf_s("%d", &num); display_sp(num); break; case '4': modify_student(); break; case '5': delete_student(); break; case '6': break; default: printf("\a"); } } while (ch != '6'); } //*************************************************************** // END OF PROJECT //***************************************************************fopen, fwrite, fread를 open, write, read로 수정한 코드입니다. 그런데 수정 함수와 삭제 함수에서 에러가 나는데 왜 그런지 이유를 알 수 없습니다.

나도이젠맥북오우너 · Answer

브레이크포인트걸고 각변수에저장되어있는값을확인해봅시다

파일 입출력을 라이브러리 입출력에서 시스템 입출력으로 바꾼 코드입니다.

1개의 답변

#systemcall 목록