Writing an algorithm that doesn't use to many if clauses

**Obvious Guy** · 12-25-2020

I am pretty new to c++ and I am trying to implement an efficient sorting algorithm. I want this to also work for four players but at the moment I am testing my program for 2 players. Each player has a goals and balls and an id. If for example player 1 has more goals than player 2 player two is the winner. If player 1 and player 2 have the same amount of goals then the player with the most amount of balls is the winner. If player 1 and player 2 have the same amount of goals and balls then the player with the highest id wins.
This is what I have come up with if there are two players. It's a pretty long if.
If there are 3 or 4 players I would end up with way to many if clauses which would make my code unreadable ?
Is there a more efficient way to do this?
I would really want to know since I plan to do it with three and four players.

in my example player with id 2 would win since both of them have the same amount of goals but player with id: 2 has more balls.

Code:

results[2]; // array or vector of type int
players[0].goals = 4;
players[0].balls = 3;
players[0].id = 1;
players[1].goals = 4;
players[1].balls = 4;
players[1].id = 2;

if(players[0].goals > players[1].goals) {
    results[0] = players[0].id;
    results[1] = players[1].id;
}
else if(players[1].goals > players[0].goals) {
    results[0] = players[1].id;
    results[1] = players[0].id;
}
if(players[0].goals == players[1].goals) {
    if(players[0].balls > players[1].balls) {
        results[0] = players[0].id;
        results[1] = players[1].id;
    }
    else if(players[1].balls > players[0].balls) {
        results[0] = players[1].id;
        results[1] = players[0].id;
    }
    else if(players[0].balls == players[1].balls) {
        if(players[0].id > players[1].id) {
            results[0] = players[0].id;
            results[1] = players[1].id;
        }
        else {
             results[0] = players[1].id;
            results[1] = players[0].id;
        }
       
    }
}

**john.c** · 12-25-2020

Instead of using a bunch of ifs, write a proper sort routine (selection or insertion sort, for example, which are good for small containers) or use std::sort.

Code:

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
 
struct Player { int goals, balls, id; };
 
int main() {
    vector<Player> players {
       { 4, 3, 1 },
       { 4, 4, 2 },
       { 5, 3, 3 },
       { 5, 3, 4 }
    };
 
    sort(players.begin(), players.end(),
        [](const auto& a, const auto& b) {
            if (a.goals > b.goals) return true;
            if (a.goals < b.goals) return false;
            if (a.balls > b.balls) return true;
            if (a.balls < b.balls) return false;
            return a.id > b.id;
        });
 
    for (auto& p: players)
        cout << p.goals << ' ' << p.balls << ' ' << p.id << '\n';
}

**Obvious Guy** · 12-27-2020

Hello, Thank yo for your answer.
I don't really understand the sorting algorithm
Why do we return true and why do we return false?

**stahta01** · 12-27-2020

std::sort - cppreference.com

Thread: Writing an algorithm that doesn't use to many if clauses

Thread Tools

Search Thread

Display

Writing an algorithm that doesn't use to many if clauses

Similar Threads

TGA RLE compressing ( writing ) algorithm on c++

max heapify and build max_heapify algorithm doesn't work as expected.

Writing to a file, it doesn't seem to be working for me...

Writing BMP file... doesn't work correctly

writing a newline to a file doesn't actually output a new line

Tags for this Thread