Sort and reverse a vector – OOP in C++ Practice

Let the standard library do the work: a vector and two algorithms.

What to build

A program that stores numbers in a vector and uses sort and reverse on them.

Requirements

Store the numbers in a vector<int> with push_back.
Print the size and the sum.
Print the numbers in increasing order, then in decreasing order, using sort and reverse.

Input

The first line has n. The second line has the n numbers.

Output

Four lines: size N, sum S, the increasing order and the decreasing order.

Constraints

1 ≤ n ≤ 1000, and each number is from -1000000 to 1000000.

Example

Input:

5
3 1 4 1 5

Output:

size 5
sum 14
1 1 3 4 5
5 4 3 1 1

Why it works

sort and reverse work on any range given by begin() and end(), so there is no loop to write and no index to get wrong.

Examples

Example 1 · Input

5
3 1 4 1 5

Expected output

size 5
sum 14
1 1 3 4 5
5 4 3 1 1

Example 2 · Input

1
-2

Expected output

size 1
sum -2
-2
-2

Hints

Hint 1

Read the numbers with `push_back`, and add them up in a range-for loop.

Hint 2

`sort(v.begin(), v.end())` puts them in increasing order, and `reverse(v.begin(), v.end())` turns the vector around.

Solution

Show one correct solution (try it yourself first)

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

void print(const vector<int>& v) {
    for (int x : v) cout << x << " ";
    cout << endl;
}

int main() {
    int n;
    cin >> n;
    vector<int> v;
    for (int i = 0; i < n; i++) {
        int x;
        cin >> x;
        v.push_back(x);
    }
    long long sum = 0;
    for (int x : v) sum += x;
    cout << "size " << v.size() << endl;
    cout << "sum " << sum << endl;
    sort(v.begin(), v.end());
    print(v);
    reverse(v.begin(), v.end());
    print(v);
    return 0;
}

Lesson: The standard library: vector, string, map and sort →