$#doanthevu$

Code câu 3 :

#include <bits/stdc++.h>
#define ll long long
using namespace std;
int main() {
    ll n, qq = 0;
    cin >> n;
    while (n >= 1) {
        cout << n << " ";
        if (n % 2 == 0) 
        {
            qq++;
        }
        n--;
    }
    cout << endl;
    cout << "So luong so chan: " << qq << endl;
    return 0;
}

Code câu 4 :

#include <bits/stdc++.h>
#define ll long long
using namespace std;
void rr(ll n) {
    for (ll i = 1; i <= n; i++) 
    {
        cout << i << " ";
    }
    cout << endl;
}
ll qq(ll n) {
    ll sum = 0;
    for (ll i = 1; i <= n; i++) {
        sum += i;
    }
    return sum;
}
int main() {
    ll n;
    cin >> n;
    rr(n);
    ll tong = qq(n);
    cout << "Tong cac gia tri tu 1 den " << n << ": " << tong << endl;
    return 0;
}

Code bài 5 :

#include <bits/stdc++.h>
#define ll long long
using namespace std;
int main() {
    ll n, sum = 0, i = 1;
    cin >> n;
    do {
        sum += i;
        i += 2;
    } while (i <= n);
    if (sum >= 30) 
    {
        cout << "Tong cac so le tu 1 den " << n << " la: " << sum << endl;
    }
    else 
    cout << "-1" << endl;
    return 0;
}

Câu 3

#include <iostream>
using namespace std;
int n, a, dem = 0;
int main() 
{
    cin >> n;
    a = n;
    while(n--)
    {
        cout << a - n << " ";
        if((a-n) % 2 == 0) dem++;
    }
    cout << "\nCac so chan co trong day la " << dem;
    return 0;
}

Câu 4

#include <iostream>
using namespace std;
int n, dem = 0;
int tt()
{
    int tam = 0;
    for(int a  = 1; a <= n; a++)
        tam += a;
    return tam;
    
}
int main() 
{
    cin >> n;
    for(int a = 1; a <= n; a++) cout << a << " ";
    cout << "\n" << tt();
    return 0;
}

Câu 5

#include <iostream>
using namespace std;
int n, tong = 0;
int main() 
{
    cin >> n;
    do
    {
        if(n % 2 == 1) 
        {
            tong += n;
            n -= 2;
        }
        else n--;
    }
    while(n >= 1);
    if(tong > 30) cout << tong;
    return 0;
}

$#khanhtaon$