标准输入输出流
int getchar(void);
int putchar(int ch);
char * gets(char * buffer);
int puts(const char * string);
文件输入输出流
int getc(FILE * stream);
int putc(int ch, FILE * fp);
int fscanf (FILE * stream, const char * format, [argument...]);
int fprintf (FILE * stream, const char * format, [argument]);