Last and first digit prolem

i’m trying to submit this problem and with all the custom inputs its working fine but when i submit it shows wrong answer but why??

here is my code :

#include<bits\stdc++.h>
#define ll long long
using namespace std;

int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	ll t;
	cin>>t;
	while(t--){
	    ll n;
	    cin>>n;
	    int last=0,first=0;
	    last=n%10;
	    while(true){
	        n/=10;
	        if(n/10==0){
	            first=n;
	            break;
	        }
	    }
	    cout<<first+last<<"\n";
	}
	
	return 0;
}

Contest Page | CodeChef ? It gives the wrong answer for single digit numbers.

i tried it for single digit too but its still showing correct output

Not for me it isn’t:

[simon@simon-laptop][18:53:35]
[~/devel/hackerrank/otherpeoples]>./compile-latest-cpp.sh 
Compiling black_jack002-FLOW004.cpp
Executing command:
  g++ -std=c++17 black_jack002-FLOW004.cpp -O3 -g3 -Wall -Wextra -Wconversion -DONLINE_JUDGE -D_GLIBCXX_DEBUG    -fsanitize=undefined -ftrapv
black_jack002-FLOW004.cpp: In function ‘int main()’:
black_jack002-FLOW004.cpp:14:15: warning: conversion from ‘long long int’ to ‘int’ may change value [-Wconversion]
   14 |         last=n%10;
      |              ~^~~
black_jack002-FLOW004.cpp:18:23: warning: conversion from ‘long long int’ to ‘int’ may change value [-Wconversion]
   18 |                 first=n;
      |                       ^
^R
Successful
[simon@simon-laptop][18:53:50]
[~/devel/hackerrank/otherpeoples]>echo "1
3" | ./a.out
3

(The first digit of 3 is 3; the last digit of 3 is 3; so the sum of the first and last digit is 6).

1 Like

i don’t get it . when i try 3 its giving me correct solution.

here have a look :