How do you sort arrays

Question

as in how do you sort the values by value? as in if I had 3 numbers 7,30,2. How would I use a sort method to make it 2, 7, 30?

Answer 1

You could do something like this:

#include <iostream>
#include <vector>

template<typename Iter>
void sort(Iter begin, Iter end){
for(Iter b = begin; b != end - 1; ++b){
for(Iter e = b+1; e != begin; --e){
if(*(e-1) > *e){
std::swap(*(e-1), *e);
}
}
}
}

int main(){

std::vector<int> numbers{7, 30, 2};

sort(numbers.begin(), numbers.end());

for(auto &n: numbers)
std::cout << n << " ";
}

or if you're really lazy just include <algorithm> and use that sort.

Answer 2

C++11 by Bo Qian on youtube has some nice stuff, I also recommend the book Effective Modern C++ by Scott Meyers. I also use the site https://www.codingame.com. There are alot of good players there and alot of the code is visible after you complete challenges, allowing you to pick up some new tricks.

Answer 3

thr r some easy techniques like selection sort and bubble sort apply them!!

Answer 4

Use two for loops and use it to find the lowest and set that equal to the zero index of your array and then do the same for the other one.

Answer 5

Well the second one will be a little different.

Answer 6

im not following with the for loops

Answer 7

@Dennis could you explain the <algorithm> sort. it's spassing when I just throw in the three numbers

Answer 8

@M.A gleason

#include <iostream>
#include <vector>
#include <algorithm>

int main(){
std::vector<int> numbers{7 , 30, 2};

std::sort(numbers.begin(), numbers.end());

for(auto &n: numbers) // This requires c++11
std::cout << n << " ";
}

Hopefully I didn't make any typos ^^

Answer 9

I'm getting the exception

|error: conversion from 'int' to non-scalar type 'std::vector<int>' requested|

I wrote
std::vector<int> numbers[3] = {one,two,three};
std::sort(numbers.begin(),numbers.end());

Answer 10

Please post your code.

Answer 11

#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

/*Roundabout way of sorting

void sorter(int *oneV, int *twoV, int *threeV) {

int oneH = *oneV, twoH = *twoV, threeH = *threeV;

if (oneH < twoH && oneH < threeH){
*oneV = oneH;
cout << "Hit 1 ";
if (twoH < threeH){
*twoV = twoH;
*threeV = threeH;
cout << "2 3 \n";
}else{
*twoV = threeH;
*threeV = twoH;
cout << "3 2 \n";
}
}else if (twoH < oneH && twoH < threeH){
*oneV = twoH;
cout << "Hit 2 ";
if (oneH < threeH){
*twoV = oneH;
*threeV = threeH;
cout << "1 3 \n";
}else{
*twoV = threeH;
*threeV = oneH;\
cout << "3 1 \n";
}
}else if(threeH < oneH && threeH < twoH){
*oneV = threeH;
cout << "Hit 3 ";
if (twoH < oneH){
*twoV = twoH;
*threeV = oneH;
cout <<
}else{
*twoV = oneH;
*threeV = twoH;
}
}
}*/

int main()
{
int one, two, three;
bool test = false;
do {
cout << "Enter three numbers to find median." << endl;
cin >> one;
cin >> two;
cin >> three;

if (((one >= 1) && (one <= 20)) && ((two >=1) && (two <= 20)) && ((three >= 1) && (three <= 20))){
test = true;
}else {

cout << "incorrect numbers, try again." << endl << endl << endl << endl;
test = false;
}
} while (test == false);
/*sorter(&one,&two,&three);*/
std::vector<int> numbers[3] = {one,two,three};
std::sort(numbers.begin(),numbers.end());
cout << numbers[0] << " " << numbers[1] << " " << numbers[2];

} Ignore the roundabout way, I'm trying to do that without making an entire function. I'm trying to learn how to do stuff faster, not bre

Answer 12

You do not need [3], vector is a dynamic array, so it resizes itself while you add to it.

you also don't need to use std:: because you used
using namespace std

Answer 13

Thought I didn't, but t didn't like me the first time, so i just copy pasta'd yours to be sure

Answer 14

@Dennis do you need C++11 to do _all_ of that, or just the for loops you showed? Because new error came up.

|70|error: in C++98 'numbers' must be initialized by constructor, not by '{...}'|
|70|error: could not convert '{one, two, three}' from '<brace-enclosed initializer list>' to 'std::vector<int>'|

Answer 15

c++11 is needed for the way I outputted everything.
You need at least c++0x for the vector initialization

I highly recommend upgrading, it'll make life so much easier.

for c++98 you can do this:

std::vector<int> numbers(3); //Initial size of 3

for(int i = 0; i < numbers.size(); ++i){
std::cout << "Input number " << i + 1 << ": ";
std::cin >> numbers[i];
}

std::sort(numbers.begin(), numbers.end());

for(int i = 0; i < numbers.size(); ++i){
std::cout << numbers[i] << " ";
}

Answer 16

@Dennis code::blocks has me running '98, where can I find an upgrade for free/cheap.

Answer 17

In codeblocks you can go to Settings -> Compiler and in Compiler settings you can check "Have g++ follow the c++11 ISO C++ language standard". If you do not, redownload it.

Answer 18

"Have g++ follow the C++11 ISO C++ language standard [-std=c++11]"?

Answer 19

Yes , that one

Answer 20

AHA! it works now! Thank you so so much @Dennis! Do you have discord, because there's a coders server I'm in and we'd love to have you