设计实现对文件 file.txt的读取功能，实现对文件中的整行读取和写入(不可用fscanf，fprintf函数，只可以fread和fwrite)-Design to read file file.txt function on the entire line of the file reads and writes (unavailable fscanf, fprintf function can only fread and fwrite)

给出printf，scanf，putc,gets,getchar,fprintf,fscanf,getline等函数的功能-Given printf, scanf, putc, gets, getchar, fprintf, fscanf, getline function, such as the function