help me to write program c++

Try thinking about the problem in non-programming terms and write on paper the steps needed to accomplish this. You can then work through those steps to check that your logic is correct before converting to actual C++ code.

1. The first input loop uses the wrong index

cin>> arr[5]
// here   ^ 

2. Typo in second loop header:

for(int j=0;i<5;j++)
// here     ^

3. One line later, same error as described in 1.

4. The whole code block after the input refers to single array elements using the index values i and j, but these values are never changed - you are missing a loop here.

Think about what a half adder does, and then how you call it. Rather than write the code for the half adder into main(), write a separate function, and call that from main - remember that as you have 5 digits to deal with, you need to call that half adder at least 5 times.

I'd think that most of the above paragraph should be in your instructions already, or in whatever book the instructor is basing the lessons on. Look there for more details.

Here is what is wrong.Array Index starts from 0 not 1 so if you have something like

int ar[5];
int ar1[5];

and if want to access 5th element then you should do like

cin>>ar[4];
cin>>ar[4];

and in this programe i thing you should do something like

cout<<"Enter the First Binary number:<< endl;
for(int i=0;i<5;i++)
cin>>ar[i];

Now the if statment

if(ar[i]+ar1[j]==0)

does not make any sense as value of i and j is 5 and max index of array is 4. So asRichard
Said Spend some time with books.