I'ld like to create a function that passes not a std::string by reference to be modified,
void changeStr(std::string &str)
{
str = "Hello World!";
}
, but rather an entire, fixed-sized array of std::strings (the function will do exactly the same: attribute some specific strings to each space in the array). But I don't know which is the appropriate syntax...
Since you're using C++ you probably want to pass a collection of values by reference instead of a collection of references by reference. The easiest way to achieve this is to use std::vector<T>
void changeStr(std::vector<std::string>& collection) {
if (collection.size() > 0) {
collection[0] = "hello world";
}
}
collection.size() > 0, the !collection.empty() sounds better. ;-)
collection[100], make sure collection.size() > 100, etc, etc
#include <vector> should be added for this method to work.Here's how!
//Change the 10 to whatever size you'd like
void changeStr(std::string (&str)[10]) {
}
This of course, is for a static size, the other answers, however, are better methods accomplishing what you need with flexibility.
One approach would be to pass a reference to an std::array<std::string, N> where N is the size of the array. You can use a function template to deduce N:
#include <array>
template <size_t N>
void changeStr(std::array<std::string, N>& strings)
{
// access strings[i] for i >= 0 and i < N
}
alternatively, you can pass fixed size plain arrays, again using function template:
template<size_t N >
void changeStr( std::string (&strings)[N] )
{
// access strings[i] for i >= 0 and i < N
}
Note that the template is necessary here to allow for the function to work with fixed sized arrays of different sizes. The template allows you to keep the size information without having to worry about it's actual value.
std::string[10] doesn't decay to a pointer. See my code where it compiles and disallows a std::string[3] to be passed in.10. I realise my wording is poor, but the template is needed.void changeStr(std::string pStrings[], int num)
You can pass any C array of any size. If the changeStr function needs to know the size, you need to pass it as a size parameter. Note that personally I prefer to use a vector.
