Question

I am trying to assign the min value of a char to a variable of type char array like this

char charchar_value[MAX_VARCHAR_LENGTH + 1]= CHAR_MIN;

it gives me this error “incompatible types in assignment of ‘char’ to ‘char [513]’”

Answer 1

Initialization of array object requires the use of brace initializer list, i.e. something along the lines of

char charchar_value[MAX_VARCHAR_LENGTH + 1] = { val_0, val_1, /*...*/ val_n };

This would initialize the first n values to their respective values and all others to zero. This isn’t quite what you want. The only way to set the values in the array is after its initialization, using e.g. std::fill():

std::fill(std::begin(charchar_value), std::end(charchar_value),
          std::numeric_limits<char>::min());

Since there is another suggestion recommending the using essentially a C approach:

• The use of memset() is limited to types without any C++ features (as is, indeed the case for char) and when setting the value to something other than 0 it is pretty much limited to char (yes, I realized that there are cases where it would still work). std::fill() on the other hand, works with any type which is CopyAssignable and with any value given to an object of the corresponding type.
• Although the use of sizeof() work in this case, it won’t work the moment the size becomes dynamic but the compiler would still happily accept the code. Getting the std::begin() or std::end() of a pointer would fail.
• In a context where the type isn’t exactly know, e.g. when it is a typedef or within a template, std::numeric_limits<T>::min() has a better chance to work. It still won’t work for many type as there is not min() defined but the scope is bigger.

All that said, I would just use an appropriate class instead which does the initialization directly, i.e.

std::vector<char> charchar_value(MAX_VARCHAR_LENGTH + 1,
                                 std::numeric_limits<char>::min());

This allocate the memory dynamically, though, i.e. it isn’t entirely equivalent. However, unless there is a good reason to assume otherwise, I would use the simple approach and only optimize if it is necessary.