ç迭代结构数组 [英] C iterate array of struct

问题描述

说我有一个声明结构

struct mystruct {
  char a[10];
  double b;
} 

struct mystruct array[20] = { 
   {'test1',1.0},
   {'test2',2.0}  <---- I just want to declare 2 items first because I am going to add new ones later.
};
int i;
for( i=0; array[i].a != NULL ;i++){ 
    ....  <--- so here I just want to display what is initialized first
} 

然而，在for循环显示过去的2个项目（即20个项目，但所有其余的都是垃圾）。我只是想显示目前只什么被初始化，即使我宣布以存储其中的20。怎么做？谢谢。

However, the for loop display past the 2 items ( ie to 20 items but all the rest are garbage ). I just want to display currently only what is initialized, even though i declared to store 20 of them. How to do it? thanks.

我使用C90标准。
此外，假设我在加入未来更多的项目，但仍比少20个项目，我想只是想显示，直到这是有效的最后一个项目。

I am using C90 standard. Also, let's say I added more items in future , but still lesser than 20 items, i would just want to display until the "last item that is valid" .

推荐答案

有关编译器将接受初始化语法（这应该是任何标准的C编译器），你应该能够这样写：

For compilers that will accept the initializer syntax (that should be any standard C compiler), you should be able to write:

struct mystruct
{
  char a[10];
  double b;
};  // semi-colon added!

struct mystruct array[20] =
{ 
   { "test1", 1.0 },  // character strings!
   { "test2", 2.0 },
};
enum { ARRAY_SIZE = sizeof(array) / sizeof(array[0]) };

int i;
for (i = 0; i < ARRAY_SIZE && array[i].a[0] != '\0'; i++)
{ 
    printf("[%s] => %f\n", array[i].a, array[i].b);
}

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