cout语句中'\n'与endl的作用有什么区别没有?

它们之间有什么区别呢?
以下程序原本输出为:
how about the story?
its very interesting.
为什么不是:
its very interesting.
how about the story?
但是把"\n"改为endl后输出为:
its very interesting.
how about the story?


程序:
#include "string.h"
#include "stdio.h"
#include "iostream.h"
class cstr
{
    char data[100];
public:
    void showme(void)
    {cout<<"its very interesting."<<"\n";}  ////////把"\n"改为endl它们有什么不同呢?
    char *get(void);
    int getlength(void);
    void cpy(char *s);
    void cat(char *s);
};
void main(void)
{
    cstr string1,string2;
    string1.showme();
    string1.cpy("how about ");
    string2.cpy("the story?");
    string1.cat(string2.get());
    puts(string1.get());
}
char *cstr::get(void)
{
    return data;
}
int cstr::getlength(void)
{
    return strlen(data);
}
void cstr::cpy(char *s)
{
    strcpy(data,s);
}
void cstr::cat(char *s)
{
    strcat(data,s);
}