各位仁兄帮帮我,这个编程哪错了?c

#include<stdio.h>

#include<string.h>

#include<ctype.h>

#include<conio.h>

char xx[80];

char delwords[5][21]={"a","is","in","the","an"};

void ReverseWord(void)

{ int j,k,len;

char *p,word[21];

char buf[80], str[80];

memset(buf,0,80);

memset(str,0,80);

p=xx[20];

j=0;

memset(word,0,21);

while(*p){

if(isalpha(*p))

{word[j++]=*p++;

if(*p)continue;

}

for(k=0;k<5;k++)

{if(stricmp(word,delwords[k])==0)

break;

}

if(k==5)

{len=strlen(word);

if(len>=5)

{if(islower(word[0]))

word[0]=toupper(word[0]);

}

strcpy(buf,word);

strcat(buf," ");

strcat(buf,str);

strcpy(str,buf);

}

j=0;

memset(word,0,21);

while(*p&&(!isalpha(*p)))

p++;

}

strcpy(xx[80],str);

}

void main()

{char xx[80]={"today is sunny you know?"};

ReverseWord();

printf("%s",xx[80]);

}

两个错误：

1、p=xx[20];

p是指针，xx[20]是字符，不可赋值。

2、strcpy(xx[80],str);

strcpy需要字符数组或指针为参数，而xx[80]不是