strlen和sizeof

#include<iostream>#include<string.h>using namespace std; int main(){char a[9] = "Hello";cout<<sizeof(a)<<" "<<strlen(a)<<endl; char b[] = "Hello";cout<<sizeof(b)<<" "<<strlen(b)<<endl;char *c = "Hello";cout<<sizeof(c)<<" "<<strlen(c)<<endl;return 0;} 

sizeof(c) 应该是指针的大小，应该和系统或编译器有关4或者8。