you wrote If(A>B), it should be if(A>B) but I have a feeling that was only a typo.
printf or cout are good ways to tell if your program has satisfied a particular if condition. If you are triggering the printf, then your condition must be true.
Try this:
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printf("A is: %i and B is: %i\n", A,B)
if(A>B)
{
printf("You win");
}
elseif(A<B)
{
printf("You lose");
}
elseif(A=B)
{
printf("Its a tie");
}
If you are still not getting what you've expected, then you've messed up your control structure some how.