c程序如何打印由结构变量持有的char数组？

How do I print the char array held in the struct variable char binary_filename?

如何打印struct variable char binary_filename中保存的char数组?

I tried:

printf("Binary file name is : %s \n", prv_instance_t.binary_filename);

However, I get the error error: expected expression before ‘prv_instance_t’

但是,我收到错误错误:'prv_instance_t'之前的预期表达式

Here is the struct definition.

这是结构定义。

#define BINARY_FILE_NAME_MAXLEN   10 

typedef struct _prv_instance_
{
    /*
     * The first two are mandatories and represent the pointer to the next instance and the ID of this one. The rest
     * is the instance scope user data (uint8_t power in this case)
     */
    struct _prv_instance_ * next;   // matches lwm2m_list_t::next
    uint16_t shortID;               // matches lwm2m_list_t::id
    uint8_t  power;
    uint8_t  reset;
    double   dec;
    char binary_filename[BINARY_FILE_NAME_MAXLEN];
} prv_instance_t;

2 个解决方案

#1

You are using the type itself. To access a member of the struct you have to declare an instance of that struct first. For example, this will print Hello World :

您正在使用该类型本身。要访问结构的成员,您必须首先声明该结构的实例。例如,这将打印Hello World:

#include <stdio.h>
#include <string.h>

#define BINARY_FILE_NAME_MAXLEN 10

typedef struct _prv_instance_
{
    char binary_filename [BINARY_FILE_NAME_MAXLEN];
} prv_instance_t;


int main()
{
    prv_instance_t foo, bar;
    strcpy(foo.binary_filename, "Hello");
    strcpy(bar.binary_filename, "World");

    printf("%s %s\n", foo.binary_filename, bar.binary_filename);
    return 0;
}

What you are trying to do is similar to

你想要做的是类似的

printf("%d", int);

#2

Just remove typedef keyword.

只需删除typedef关键字即可。

Current definition does not define a variable, but makes two equivalent types prv_instance_t and struct _prv_instance_. From your question I understand that prv_instance_t should be an instance (variable) of type _prv_instance_, keyword typedef is unnecessary.

当前定义不定义变量,而是生成两个等效类型prv_instance_t和struct _prv_instance_。根据您的问题,我了解prv_instance_t应该是_prv_instance_类型的实例(变量),关键字typedef是不必要的。

Your printf will work with:

您的printf将用于:

#define BINARY_FILE_NAME_MAXLEN   10

struct _prv_instance_
{
    /*
    * The first two are mandatories and represent the pointer to the next instance and the ID of this one. The rest
    * is the instance scope user data (uint8_t power in this case)
    */
    struct _prv_instance_ * next;   // matches lwm2m_list_t::next
    uint16_t shortID;               // matches lwm2m_list_t::id
    uint8_t  power;
    uint8_t  reset;
    double   dec;
    char binary_filename[BINARY_FILE_NAME_MAXLEN];
} prv_instance_t;

as well as with the following one:

以及以下一个:

#define BINARY_FILE_NAME_MAXLEN   10

struct _prv_instance_
{
    /*
    * The first two are mandatories and represent the pointer to the next instance and the ID of this one. The rest
    * is the instance scope user data (uint8_t power in this case)
    */
    struct _prv_instance_ * next;   // matches lwm2m_list_t::next
    uint16_t shortID;               // matches lwm2m_list_t::id
    uint8_t  power;
    uint8_t  reset;
    double   dec;
    char binary_filename[BINARY_FILE_NAME_MAXLEN];
};

struct _prv_instance_ prv_instance_t;

#1