Different output on online judge - c++

Question

I was trying a problem in hackerrank(online judge). The task is to take an input string and then print the characters of the even indices first, followed by a space and then the characters in the odd indices for a given number of test cases 'n'. I was able to solve it. However I get different output on my compiler and a different one in the online judge. The output i get on my computer is correct one but i am not getting the same in the online judge. Here is my code :-
#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <string.h>
using namespace std;
int main()
{
int n;
cin>>n;
getchar();
char s[1000];
for(int i=0;i<n;i++)
{
cin.getline(s,1000);
int len;
len=strlen(s);
for(int j=0;j<=len;j++)
{
if(j%2==0)
cout<<s[j];
}
cout<<" ";
for(int m=0;m<len;m++)
{
if(m%2!=0)
{
cout<<s[m];
}
}
cout<<endl;
}
return 0;
}
Input given
1
Hacker
Output when running on my computer using g++
Hce akr
Output when running on the online judge
Hce
Please Help.
Note: 0 is considered an even index.

Answer 1

for(int j=0;j<=len;j++)
{
if(j%2==0)
cout<<s[j];
}
You wrote <= instead of <.
Here, when the word length is even (as is "Hacker"), you're accidentally printing the terminating NULL as well.
The result of this depends on your execution environment. Apparently your terminal just ignores it, and this "online judge" of which you speak does not, instead using it as a NULL terminator for your program output!! (Which is poor coding if you ask me)
N.B. You don't get program output from your compiler. You get it from executing your program, over which the compiler has no control.
Also, please, for the love of Cthulhu, indent your code and use meaningful variable names?