#include "stdio.h"
#include "string.h"
int main(int argc, char* argv[])
{
    char str1[20]="hello";
    char str2[20]="world";
    char str3[20];
    char *p,*q;
    p=str3;q=str1;
    while(*q!='\0')
    {
        *p=*q;
        p++;
        q++;
    }
    q=str2;
    while(*q!='\0')
    {
        *p=*q;//当*p=*q时，*p现在的值是由str1+str2吗？
        p++;
        q++;
    }
    *p='\0';
    puts(str3);
    return 0;
}