方法一：
此处必须使用静态变量，不然调用函数随着调用结束释放了内存空间，以至于即使返回了正确的地址内容也被清空了。而静态变量则是随着主函数结束而结束与调用函数无关。

char *getmonth( int n ){
    static char month[12][10]={				//静态数组
        "January","February","March","April","May","June",
        "July","August","September","October","November","December"
    };
    char *p=NULL;
    if(n>0&&n<=12)
        p=month[n-1];
    return p;
}

方法二：

 char *getmonth(int n)
    {
    	char *getmonth[13] = { "0", "January", "February", "March", "April", "May",
    		"June", "July", "August", "September", "October", "November", "December" };
    
    	if (n > 0 && n < 13)
    		return  getmonth[n];//返回对应字符串首地址
    	else
    		return 0;
    }