strlen和sizeof辨析

#include<stdio.h>
#include<string.h>

int main(int argc,char*argv[])
{
char ch[256]={0};
int i=0;
while(1)
{
ch[i]=getchar();

    if(ch[i]=='\n')
    {
        ch[i]='\0';
        break;
    }
    i++;
}
int len =strlen(ch);
int len1 = sizeof(ch)/sizeof(ch[0]);
int len2 = sizeof(ch);
printf("len:%d,len1:%d,len2:%d",len,len1,len2);
return 0;   

}
输入as df
输出len:5,len1:256,len2:256
1、strlen可以算空格但不会算’\0’
2、sizeof会受定义数组大小的影响，且会算入’\0’