The difference between macro and function I/Ofunction comparision(from c and pointer )-优快云博客

本文探讨了宏与函数之间的主要区别，包括执行速度、程序大小及潜在副作用等，并介绍了C语言中标准输入输出函数如getchar、putchar、scanf、printf等的使用方法。

macro is typeless and execute faster than funtion ,becaus of the overhead of calling and returnning of function,but macro will increase the size of program due to many time's substitution,as well as the side effect of macro may cause unexpected results,to avoid this ,you'd better make the arguments bracketed as possible as you can,on the contrary ,the result of function is more predicted.

macro :definitine commom argument ,little funtion such as MAX,MIN,

function :specific module or operation

getchar: ch=getchar(); fgetc()/getc()

putchar : putchar(ch); fputc()/putc()

gets: gets(*str);{\n terminate, not include \n} fgets(char *str,int n ,FILE *stream){\n terminate, include \n}only read in n-1 char the last is filled with null

puts: puts(*str);{ add \n} fputs(char *str,int n ,FILE *stream){not add \n}all of this function operating in line return a char *of target

scanf: fscanf(FILE *stream,char *format,[argument]) sscanf( string str, string fmt, mixed var1, mixed var2 ... );

printf: fprintf(FILE *stream,char *format,[argument]) sprintf( char *buffer, const char *format [, argument] … );

转载于:https://www.cnblogs.com/zeroArn/p/5452099.html