I'm looking for some guidance here. I have a project and I'm looking to sort a char vector inside a struct.

I have the next struct and the main:

struct employee
{
  long Id;
  char name[20]
};

int main ()
{
  employee data[5]
  for(int i=0; i<5; i  )
  {
    for(int x=i 1; x<5; x  )
    {
      if(data[i].name[0]> data[x].name[0])
      {
        data[i].Id = data[x].Id;
        data[i].name = data[x].name;
      }
    }
  }
}

I'm stuck in this part. What I am trying to do is to basically sort the vector alphabetically by the name. For example: brayan should be first and carlos next.

It should look like this:

Employee #1 
Id: 123
Name: brayan

Employee #2
Id: 121
Name: Carlos

I would appreciate any kind of help. The only requirement for this program is not to use std::string.

CodePudding user response：

You can use std::sort with a custom comparison function, as commented.

The comparison function:

• receives two employees, and
• returns true if the first name is alphabetically "smaller" than the second (i.e. strcmp returned < 0).

[Demo]

#include <algorithm>  // sort
#include <cstring>  // strcmp
#include <fmt/core.h>

struct employee {
    long Id;
    char name[20];
};

int main() {
    employee data[5] {
        { 200, "Bryan"},
        { 100, "Charles"},
        { 300, "Anne"},
        { 500, "Will"},
        { 400, "John"}
    };
    std::sort(data, data   std::size(data),
        [](const auto& e1, const auto& e2) { return strcmp(e1.name, e2.name) < 0; }
    );
    for (auto i{0}; i < std::ssize(data);   i) {
        fmt::print("Employee #{}\nId: {}\nName: {}\n\n",
            i 1, data[i].Id, data[i].name);
    }
}

// Outputs:
//
//   Employee #1
//   Id: 300
//   Name: Anne
//
//   Employee #2
//   Id: 200
//   Name: Bryan
//
//   Employee #3
//   Id: 100
//   Name: Charles
//
//   Employee #4
//   Id: 400
//   Name: John
//
//   Employee #5
//   Id: 500
//   Name: Will

CodePudding user response：

#include <string>
#include <vector>
#include <algorithm>

struct Test
{
    int id;
    std::string name;
};

int main()
{
    std::vector<Test> tab(5);
    std::sort(std::begin(tab), std::end(tab), []
    (const Test& lhs, const Test& rhs)
    {return lhs.name > rhs.name;});
}