What is file mode in c plus plus?

Answer 1

There are 6 main types of file opening mode:

* "r". Open file for reading and file must exist; * "w" Open file for writing. If file does not exist it is created or if life already exist it's content is erased. * "a" Open file for appending. It adds all information at the end of the file leaving old data untouched. If file does not exist it is created. * "r+" Open file for reading and writing and file must exist. * "w+" Open file for writing and reading. If file does not exist it is created or if life already exist it's content is erased. * "a+" Open file for appending and reading. Again all new data is written at the end of the file old data leaving untouched. If file does not exist it is created. (You can read old data by moving pointer in file using fseek or rewind functions from stdio.h. But all writing operations will be done at the end of the file no matter how you change pointer) It is assumed by default that file will be standard ASCII text file in order to open file as binary file, you need to add "b" indicator:

FILE *myFile = fopen("myfile.txt", "wb");

/ * following two has identical meaning */

FILE *myFile = fopen("myfile.txt", "w+b");

FILE *myFile = fopen("myfile.txt", "wb+");

Answer 2

Low-level: open/creat/close/read/write/lseek/...

High-level: fopen/fclose/fread/fwrite/fprintf/fscanf/...

Answer 3

File mode refers to whether a file is opened for reading, writing, or both, as well as whether the file is used to stored character data (e.g., plain text) or binary data (e.g., objects).

Answer 4

r- read

w- write

r+- read and write

w+- write and read

a- append

rb- read in binary

wb- write in binary