read , scanf , fgets 标准输入键盘输入区别

#include <stdio.h>
#define MAXSIZE 10

int main()
{
        char buf[MAXSIZE], patten[MAXSIZE];
        int n;

        fgets(buf,MAXSIZE,stdin); //size MAXSIZE-1

        if((n = read(0,buf,MAXSIZE-1)) < 0) //size MAXSIZE-1
                return -1;
        buf[n]='\0';

        snprintf(patten, sizeof(patten), "%%%ds", MAXSIZE);
        scanf(patten,buf); //size MAXSIZE-1

}

(gdb)x/10c buf

0x7fffffffe250: 49'1' 50 '2' 51 '3' 52 '4' 53 '5' 54 '6' 55 '7' 56 '8'

0x7fffffffe258: 57'9' 0 '\000'