LinuxQuestions.org - [SOLVED] Question with c++,string and arrays?

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Question with c++,string and arrays?

I want your opinions and also a solution for my underlying problem if possible.

Here is the problem.
I have a structure say

Quote:

struct Property
{
char name[100];
char value[100];
};

I want to execute a couple of looping statements like this

strcpy(user_property[0].name,"value1");
strcpy(user_property[0].value,((const char*)Getvalue1()));

Here Getvalue1() is a memeber function of a class that returns a string value I have to actually run a loop to assign 15 such values.This can be done if I pass array indexes so first I have to store the values value1 etc and (const char*)Getvalue1() in some array but I am not sure how to do this I tried doing the same but I have the following compilation errors

This is the sample code that I have done

PHP Code:




struct Property  user_property[2]; 
        my_Class response; 
        response.SetCode("Ajit"); 
        response.SetMQCode("Gunge"); 
        string sample = xmlrMQresponse.GetMQErrorCode(); 
        string sample1 = xmlrMQresponse.GetMQStateCode(); 
 
        const char* const list1[] = {"stateCode","errorCode"}; 
        const char* const list2[] = {sample1}; 
        const size_t len = sizeof(list1) / sizeof(list1[0]); 
        for (size_t i = 0; i <len; i++) { 
            strcpy(user_property[i].name,list1[i]); 
            strcpy(user_property[i].value,list2[i]); 
        }

The compile error I am getting is

PHP Code:




connot convert std::string to const char * in initialization

at line

PHP Code:




const char* const list2[] = {sample1};

Can someone help me with the resolution here?

Regards,
Ajit

Use "sample1.c_str()" instead of just "sample1". c_str() returns a pointer to a char buffer representing the underlying string - it's guaranteed not to change so long as you only use const methods on the string (if I remember correctly).

Also, consider abandonning strcpy() and using strncpy(), it's safer (i.e. will save you headaches later on).

@ the OP,

Unless you are developing real-time code, I would also recommend abandoning character arrays for storing strings. Just store them within an STL string.

Code:

struct Property

{

    std::string name;

    std::string value;

};

...



Property user_property[2];    // no need to specify struct in declaration



std::string sample  = "mqErrorCode";

std::string sample1 = "mqStateCode";



const std::string list1[] = { "stateCode", "errorCode" };

const std::string list2[] = { sample1 };

const size_t len = sizeof(list1) / sizeof(list1[0]);



for (size_t i = 0; i < len; ++i)

{

    user_property[i].name  = list1[i];

    user_property[i].value = list2[i];    // BUG HERE!  list2 only has one item, not two.

}

Hi dwhitney67 and dwhitney67 thanks for your responses.That helps.

Ajit