求助，函数声明出现array type has incomplete element type的编译报错
程序代码：
#include<stdio.h>
#include<string.h>
#define MAXLINE 40
char * s_gets( char * st , int n);
int sort_max_value(struct book str[],int n);
struct book
{
char title[MAXLINE];
float value;
};
int main()
{
struct book library[MAXLINE];
int maxbook;
scanf("%d",&maxbook);
int index;
for( index = 0 ; index < maxbook ; ++index)
{
scanf("%s",&library[index].title);
//s_gets( library[index].title, MAXLINE);
while( getchar() != '\n')
continue;
scanf("%f",&library[index].value);
}
sort_max_value(library,maxbook);
printf("highest price: %.1f, %s\n",library[maxbook-1].value,library[maxbook-1].title);
printf("highest price: %.1f, %s\n",library[0].value,library[0].title);
}
char * s_gets( char * st, int n)
{
char * rev_val;
char * find;
rev_val = fgets(st,MAXLINE,stdin);
if(rev_val)
{
find = strchr( st , '\n');
if(find)
*find = '\0';
else
while( getchar() != '\n')
continue;
}
return rev_val;
}
int sort_max_value( struct book str[],int n)
{
int i,k;
float temp_value;
char temp_ch[MAXLINE];
for( i = 1 ; i < n ; ++i)
{
temp_value = str[i].value;
strcpy(temp_ch,str[i].title);
for( k = i ; k > 0 && str[k-1].value > temp_value ;--k)
{
str[k].value = str[k-1].value;
strcpy(str[k].title,str[k-1].title);
}
str[k].value = temp_value;
strcpy(str[k].title,temp_ch);
}
}
代码如上，在dev上是没有报错可以正常编译运行，可以一旦到了学校的OJ上就直接编译报错
贴出报错
程序代码：
a.c:5:32: error: array type has incomplete element type
int sort_max_value(struct book str[MAXLINE],int n);
^
a.c:5:27: warning: ‘struct book’ declared inside parameter list [enabled by default]
int sort_max_value(struct book str[MAXLINE],int n);
^
a.c:5:27: warning: its scope is only this definition or declaration, which is probably not what you want [enabled by default]
a.c: In function ‘main’:
a.c:20:3: warning: format ‘%s’ expects argument of type ‘char *’, but argument 2 has type ‘char (*)[40]’ [-Wformat=]
scanf("%s",&library[index].title);
^
a.c:26:2: error: type of formal parameter 1 is incomplete
sort_max_value(library,maxbook);
^
a.c:26: confused by earlier errors, bailing out
Preprocessed source stored into /tmp/ccO6HnKI.out file, please attach this to your bugreport.感觉是不同的C版本不一样导致的，但是不知道怎么修改（晕）
