Explanation needed for FLOW004

1

Problem Link: FLOW004

Testcases:
Input
3
1234
124894
242323

Output
5
5
5

Please explain me,what wrong is with my code:
Code:

 #include <iostream>
using namespace std;

int main() 
{
int t;
cin>>t;
for(int i=0;i<t;i++)
{   unsigned long long n;
    cin>>n;
    int firstdigit;
    int lastdigit=n%10;
    while(n>=10)
    {
        n%10;
        n=n/10;
        firstdigit=n;
    }
    cout<<firstdigit+lastdigit<<endl;
}
	return 0;
}

Custom Input:

8
12345
124894
242323
12345678
123456789
1234567890
12345678901
123456789012

Output:

6
5
5
9
10
1
2
3

So,as you can see I have tried the problem with the given three test cases along with additional 5 inputs
and getting the desired output,but still my code is not getting accepted.Can anyone explain,why so?

2

//Just see my while loop.//

#include
using namespace std;

int main() {
int T;cin>>T;
int sum,lastdigit,firstdigit;
for(int i=0;i<T;i++)
{
long long int N;cin>>N;

    lastdigit=N%10;
    
    firstdigit = N;
    
    while(N>=10)
    {
        N=N/10;
    }
    
    firstdigit=N;
    
    sum=firstdigit+lastdigit;
    cout<<sum<<endl;
        
    }
}

In while you have to just divide that number untill you gets your first digit.

3

//Just see my while loop.//

#include
using namespace std;

int main() {
int T;cin>>T;
int sum,lastdigit,firstdigit;
for(int i=0;i<T;i++)
{
long long int N;cin>>N;

    lastdigit=N%10;
    
    firstdigit = N;
    
    while(N>=10)
    {
        N=N/10;
    }
    
    firstdigit=N;
    
    sum=firstdigit+lastdigit;
    cout<<sum<<endl;
        
    }
}

In while you have to just divide that number untill you gets your first digit.

1 Like
4

do the above change and rest is all right
your output is wrong for single digit no:
ex-7 then in this case according to yur code
last digit is 7 is correct but first digit has no value since you have made while loop for>=10

2 Likes
5

Thank you!!,I got it and my solution got accepted.

6

Thank you!I got it now actually my solution was not working for single digit number as pointed out by the below user. i didn’t actually set ‘firstdigit=n’ which resulted in not working for summation of the single digit number(input:7 output: sum=14,but I got the sum as ‘7’ instead.

7

hey; I tried with the below logic and test cases; still my sol is not accepted. It would be great if anyone let me know where I’m missing.

#include <stdio.h>

int main(void) {
// your code goes here
int t,n,f;
scanf("%d",&t);
while (t–){
scanf("%d",&n);
if(n<10) { printf("%d\n",n); continue; }
else if (n>=10 && n<100) f=n/10;
else if (n>=100 && n<1000) f=n/100;
else if (n>=1000 && n<10000) f=n/1000;
else if (n>=10000 && n<100000) f=n/10000;
else if (n>=100000 && n<1000000) f=n/100000;
else if (n==1000000) { printf("%d\n",1); continue; }

    printf("%d\n",n%10+f);
}
return 0;

}

NOTE: I’m trying to code without using the loop logic.

input:
6
8
12
467
1000
24232
124894