Coding Ninja Surya's Answers Lecture 6: Operators and For Loop

What is the output answers
2
15 17
32
Inside else 11 20
Inside if 11 21
0 2 4
Infinite 1s
0 0
0 1 3 4

*************Nth Fibonacci

#include<iostream>
using namespace std;


int main(){
    int a=1,b=1,n,ans=0;
    cin>>n;
    if(n==1)
        cout<<"1\n";
    else if(n==2)
        cout<<"2\n";
    else
    {
        for(int i=0;i<n-2;i++)
        {
            ans=a+b;
            a=b;
            b=ans;
        }
        cout<<ans<<'\n';
    }
    //Write your code here.
}

What is the output answers

continue
1 2
1 2 infinite loop
1 2 1 2
1 2 4 5 1 2 4 5

********************All prime nos

#include <iostream>
using namespace std;
void seive(int a[], int n)
{
    for(int i=1;i<n;i++)
        a[i]=0;
    for(int i=2;i<n;i++)
    {
        for(int j=2;j<i;j++)
            if(i%j==0)
                a[i]=1;
    }
}
int main(){

    /* Read input as specified in the question.
     * Print output as specified in the question.
     */
  int n;
    cin>>n;
    int a[n];
    seive(a,n);
    for(int i=2;i<=n;i++)
        if(!a[i])
            cout<<i<<'\n';
}


**********Check Error
Yes
No
10
Yes
Infinite loop

*******************Count Characters

#include<iostream>
using namespace std;

int main(){

    /* Read input as specified in the question.
     * Print output as specified in the question.
     */
  char ans;
    int a,b,c;
    a=b=c=0;
    ans=cin.get();
    if(ans>='a'&&ans<='z')
        a=1;
    else if(ans>='0'&&ans<='9')
        c=1;
     else
        b=1;
    while(ans!='$')
    {
        ans=cin.get();
    if(ans>='a'&&ans<='z')
        a++;
    else if(ans>='0'&&ans<='9')
        c++;
     else
        b++;
    }
    cout<<a<<' '<<c<<' '<<--b<<'\n';
}

*****************Sum or Product

#include<iostream>
using namespace std;

int main() {
    // Write your code here
    int n,c;
    cin>>n>>c;
    n++;
    if(c==1)
    {
        c=0;
        while(n--)
            c+=n;
    }
    else if(c==2)
    {
        c=1;
        while(n!=1)
        {
            n--;
            c*=n;
        }
    }
    else
        c=-1;
    cout<<c;
}

****************Terms of AP

#include<iostream>
using namespace std;

int main() {
    // Write your code here
    int n,i=1,ans;
    cin>>n;
    while(n!=0)
    {
        ans=(3*i)+2;
        i++;
        if(ans%4!=0)
        {
            cout<<ans<<' ';
            n--;
        }
    }
}

****************Reverse a no

#include<iostream>
using namespace std;

int main() {
    // Write your code here
    long long int n,temp=0;
    cin>>n;
    while(n!=0)
    {
        temp+=n%10;
        n/=10;
        temp*=10;
    }
    cout<<temp/10;
}

******************Binary to decimal


#include<bits/stdc++.h>
using namespace std;

int main() {
    // Write your code here
    long long int n,temp,i=0,ans=0;
    cin>>n;
    while(n!=0)
    {
        temp=n%10;
        if(temp)
            ans+=pow(2,i);
        i++;
        n/=10;
    }
    cout<<ans;
}

***********Decimal to Binary




/*Code by Surya a.k.a Sunny*/
/* by https://www.codechef.com/users/spsc */
#include <bits/stdc++.h>
//#include <boost/multiprecision/cpp_int.hpp>
#define lli long long
#define pb push_back
#define eb emplace_back
#define pi 3.14159265358979323846
#define MOD 1000000007
#define unbuffer cin.clear(); cin.sync();
#define foi(n)  for(lli i=0;i<n;i++)
#define foj(n)  for(lli j=0;j<n;j++)
#define test(T) lli T;cin>>T;while(T--)
#define loop(i, a, b) for(int i = (a); i<= (b); i++)
using namespace std;
//using namespace boost::multiprecision;
int main()
{
  //ios_base::sync_with_stdio(false);
   //cin.tie(NULL);
   //cout.tie(NULL);

   lli n,c=0,temp=0,ans=0;
   cin>>n;
    if(!n)
        cout<<'0';
    else
    {
   while(n%2!=1)
    {
      c++;
      n/=2;
    }
    while(n!=0)
     {
       ans+=n%2;
       n/=2;
       ans*=10;
     }
     ans/=10;
     while(ans!=0)
      {
        temp+=ans%10;
        ans/=10;
        temp*=10;
      }
      temp/=10;
      //temp*=pow(10,c);
      while(c--)
          temp*=10;
cout<<temp;
}
}


*********Square Root (Integral)


/*Code by Surya a.k.a Sunny*/
/* by https://www.codechef.com/users/spsc */
#include <bits/stdc++.h>
//#include <boost/multiprecision/cpp_int.hpp>
#define lli long long
#define pb push_back
#define eb emplace_back
#define pi 3.14159265358979323846
#define MOD 1000000007
#define unbuffer cin.clear(); cin.sync();
#define foi(n)  for(lli i=0;i<n;i++)
#define foj(n)  for(lli j=0;j<n;j++)
#define test(T) lli T;cin>>T;while(T--)
#define loop(i, a, b) for(int i = (a); i<= (b); i++)
using namespace std;
//using namespace boost::multiprecision;
int main()
{
  //ios_base::sync_with_stdio(false);
   //cin.tie(NULL);
   lli n;
   cin>>n;
   cout<<(int)sqrt(n);
 }

************Check Number sequence


/*Code by Surya a.k.a Sunny*/
/* by https://www.codechef.com/users/spsc */
#include <bits/stdc++.h>
//#include <boost/multiprecision/cpp_int.hpp>
#define lli long long
#define pb push_back
#define eb emplace_back
#define pi 3.14159265358979323846
#define MOD 1000000007
#define unbuffer cin.clear(); cin.sync();
#define foi(n)  for(lli i=0;i<n;i++)
#define foj(n)  for(lli j=0;j<n;j++)
#define test(T) lli T;cin>>T;while(T--)
#define loop(i, a, b) for(int i = (a); i<= (b); i++)
using namespace std;
//using namespace boost::multiprecision;
int main()
{
    int n,temp,i=2,no;
    cin>>n>>temp;
    bool ans=true;
    while(i<=n)
    {
        cin>>no;
        if(no==temp)
        {
            cout<<"false";
            return 0;
        }
        i++;
        if(no<temp)
        {
            if(ans==false)
            {
                cout<<"false";
                return 0;
            }
        }
        else
        {
            if(ans==true)
                ans=false;
        }
        temp=no;
    }
    cout<<"true";
}