修改作为一个指针传递一个结构 - Ç [英] Modifying a struct passed as a pointer - C
问题描述
我试图修改被作为参数传递使用指针由我不能让它工作的一个结构。我不能只返回结构,因为函数必须返回一个整数。我怎样才能修改功能的结构?这是我迄今所做的:
I'm trying to modify a struct that was passed as a parameter by using a pointer by I can't get it working. I cant just return the struct because the function must return an integer. How can I modify the struct in the function? This is what I've done so far:
typedef enum {TYPE1, TYPE2, TYPE3} types;
typedef struct {
types type;
int act_quantity;
int reorder_threshold;
char note[100];
}elem;
int update_article(elem *article, int sold)
{
if(*article.act_quantity >= sold)
{
article.act_quantity = article.act_quantity - sold;
if(article.act_quantity < article.act_quantity)
{
strcpy(article.note, "to reorder");
return -1;
}
else
return 0;
}
else if(article.act_quantity < venduto)
{
strcpy(*article.note, "act_quantity insufficient");
return -2;
}
}
的东西不是一个结构或联合'act_quantity的错误:::请求成员中的所有行,我试图修改结构
I get this error: "error: request for member: 'act_quantity' in something not a structure or union' " in all the lines where I tried to modify the struct.
我得到这个错误。
编辑:我曾用。代替 - >。我现在固定它。它仍然给我的错误:一元的无效类型参数'*'(有'诠释')
I had used "." instead of "->". I fixed it now. It still gives me an error: " invalid type argument of unary '*' (have 'int')"
推荐答案
操作precedence 导致
*article.act_quantity
是PTED为 *(article.act_quantity)
这应该是(*文章).act_quantity
或物品─&GT; act_quantity
(当LHS是指针)
It should be (*article).act_quantity
or article->act_quantity
(when the LHS is a pointer)
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