std::string mstring[5];
        mstring[0] = "veena";
        mstring[1] = "guitar";
        mstring[2] = "sitar";
        mstring[3] = "sarod";
        mstring[4] = "mandolin";

I want to assign the array like above. I don't want to do it at initialization but assign later. Is there a way to combine 5 statements into one.

CodePudding user response：

You can do that by using std::array<std::string, 5> instead of the raw array.

For example

#include <iostream>
#include <string>
#include <array>

int main()
{
    std::array<std::string, 5> mstring;
    
    mstring = { "veena", "guitar", "sitar", "sarod", "mandolin" };

    for ( const auto &s : mstring )
    {
        std::cout << s << ' ';
    }
    std::cout << '\n';
}

The program output is

veena guitar sitar sarod mandolin 

Another approach when a raw array is used is to use std::initializer_list in range-based for loop. For example

#include <iostream>
#include <string>

int main()
{
    std::string mstring[5];
    
    size_t i = 0;

    for ( auto s : { "veena", "guitar", "sitar", "sarod", "mandolin" } )
    {
        mstring[i  ] = s;
    }

    for ( const auto &s : mstring )
    {
        std::cout << s << ' ';
    }
    std::cout << '\n';
}

The program output is the same as shown above

veena guitar sitar sarod mandolin 

If your compiler supports C 20 then instead of these statements

size_t i = 0;

for ( auto s : { "veena", "guitar", "sitar", "sarod", "mandolin" } )
{
    mstring[i  ] = s;
}

you can use just one range-based for loop

for ( size_t i = 0; auto s : { "veena", "guitar", "sitar", "sarod", "mandolin" } )
{
    mstring[i  ] = s;
}

CodePudding user response：

This is a two-liner, but I think one-lining is not possible with native arrays (at least to my best knowledge).

1. Initialize a temporary array with the desired values
2. swap pointers with the original array

In that way you can use the one-line initialization for arrays, but still can manipulate the original array before setting the values.

#include <string>
#include <iostream>

int main(){
    
  std::string mystring[5];
  std::string tmp[5] = {"veena","guitar","sitar", "sarod", "mandolin"};
  std::swap(mystring, tmp);
  for(auto& s : mystring) std::cout << s << std::endl;
  return 0;
}

CodePudding user response：

You can use comma operator to combine multiple expressions into one statement.

mstring[0] = "veena",
mstring[1] = "guitar",
mstring[2] = "sitar",
mstring[3] = "sarod",
mstring[4] = "mandolin";