我这个c语言程序哪里错了

#include <stdio.h>

char *getmonth( int n );

int main()
{
int n;
char *s;

scanf("%d", &n);
s = getmonth(n);
if ( s==NULL ) printf("wrong input!\n");
else printf("%s\n", s);

return 0;

}

/* 你的代码将被嵌在这里 */

char *getmonth( int n )
{
char *p;
int i;
char a[13]={"a","January","February","March","April","May","June","July","August","September","October","November","December"};
p=a;
if(n<=12&&n>=1)
{
for (i=1;i<=n;i++)
{
p++;
}
return p;
}
else return NULL;

}

供参考：

#include <stdio.h>
char* getmonth(int n);
int main()
{
    int n;
    char* s;
    scanf("%d", &n);
    s = getmonth(n);
    if (s == NULL) 
        printf("wrong input!\n");
    else 
        printf("%s\n", s);
    return 0;
}

// 你的代码将被嵌在这里 

char* getmonth(int n)
{
    char* a[13] = { "0","January","February","March","April","May","June",
                 "July","August","September","October","November","December" };
    if (n <= 12 && n >= 1)
        return a[n];
    else 
        return NULL;
}