I declared an array of size 100 string bin[100]; I want each array to be initialized as "". How do I initialize all of them with one line? I tried something like bin[] = ""; and it doesn't work. Any help would be appreciated.
Default Constructor
RandomString()
{
input = "";
//bin[] = "";
}
You don't have to do anything special, just string bin[100]; is fine. The default constructor for std::string will be called for each element of the array.
If the array is a member of some class, initialize it in the member initialization list:
struct SomeClass
{
std::string bin[100];
SomeClass() : bin() // You can initialize arrays with () in the mem-init list
{
}
};
*Technically, the default constructor will be called even if you don't add bin() to the mem-init list, but it is good practice (as built-in types will be left uninitialized).
In C++, members of a class are initialized through initialization lists. For example, in the following examples, there is a difference in the code:
// First example
struct MyClass
{
int i;
SomeClass() : i(1)
{
}
};
// Second example
struct MyClass
{
int i;
SomeClass()
{
i = 1;
}
};
In the first example, i is initialized to 1 in the initialization list. In the second example, 1 is assigned to i. You could think of the above code as doing the following:
int i = 1; // First example
int i; // Second example
i = 1;
For a built-in type like int there isn't much difference between the two, however the difference above can be very important in some situations, such as when the member is declared const:
struct SomeClass
{
const int i;
SomeClass()
{
i = 1; // Error!!
}
};
In the above example, the const member must be initialized in the initialization list.
string bin[100];as my member function would I just leave the initialization blank in the class constructor?
bin is a member variable and not a function. Initialize it in the member initialization list of the ctor, for example MyClass::MyClass() : bin() {//body of ctor}RandomString() : bin() { }.someclass(std::string v[100]) is the same as someclass(std::string* v). You cannot use the pointer to initialize the member array. The best you can do is a for loop or some other construct like std::copy to copy each element into the array.In your way, you just initialized the first element of the array, the default ctor initialize to null string. You want to initialize the 100 elements, just do the same thing for each of them.
