assignment of array pointer in a class

Question

void SetString(char s1[], char s2[]){
    str1= s1[]; 
    str2= s2[];

}
private: 
    char str1[20];
    char str2[20];

What's wrong in that code please some one tell me.

Its giving me following error:

stringhandler.cpp: In member function ‘void StringHandler::SetString(char*, char*)’:

stringhandler.cpp:25: error: expected primary-expression before ‘]’ token stringhandler.cpp:26: error: expected primary-expression before ‘]’ token

enter image description here

Answer 1

You can't copy C-strings like that, s1 and s2 both decay to a pointer and you have to use strcpy to copy them:

strcpy(str1, s1);
strcpy(str2, s2);

But you're working with C++ so really you should be using std::string:

void SetString(const std::string& s1, const std::string& s2)
    {
        str1= s1; 
        str2= s2;

    }
private: 
    std::string str1;
    std::string str2;

or, for C++11 and higher:

void SetString(std::string s1, std::string s2)
    {
        str1= std::move(s1); 
        str2= std::move(s2);

    }

This solves a lot of problems that come with C-strings for you.

Answer 2

You can not do str1=s1[]. It is not valid. Use this instead to copy an array to another:

void SetString(char s1[], char s2[]){
    std::copy(s1, s1+20, std::begin(str1));
    std::copy(s2, s2+20, std::begin(str2));
}

---

Even better, use std::array instead (if your case is general) or std::string if you are dealing with strings as array of char. Something like this:

void SetString(const std::array<char,20>& s1, const std::array<char,20>& s2){
    str1=s1;
    str2=s2;
}
private: 
    std::array<char,20> str1;
    std::array<char,20> str2;

---

or:

void SetString(const std::string& s1, const string& s2){
    str1=s1;
    str2=s2;
}
private: 
    std::string str1;
    std::string str2;