Pawn movement error - c++

Question

I had recently started working on a chess engine in c++ for an university project but i have a problem in my pawn movement function. I know that the pawn is supposed to move one square forward or attack one square in diagonal. Well my function allows the pawn to attack blank spaces and i do not know why. My board is divided in 2 pieces: one that remembers which player a piece belongs to and one that has the name of the piece (like q,Q,p,P... and blank spaces). A hint would be more than welcome. (sorry for my poor English skills)
The code looks like this:
bool move_P(int move_start_i, int move_start_j, int move_finish_i, int move_finish_j, char table[][9])
{
switch (table[move_finish_i][move_finish_j])
{
case ' ':
{
if (move_start_i - 1 == move_finish_i) // move pawn
{
return true;
}
}
default:
{
if (move_finish_i == move_start_i - 1 && move_finish_j == move_start_j - 1) // atack pawn ^<-
{
if (player[move_finish_i][move_finish_j] == player[move_start_i - 1][move_start_j - 1])
{
return false;
}
else
{
return true;
}
}
else if (move_finish_i == move_start_i - 1 && move_finish_j == move_start_j + 1) // atack pawn ->^
{
if (player[move_finish_i][move_finish_j] == player[move_start_i - 1][move_start_j + 1])
{
return false;
}
else
{
return true;
}
}
}
}
return false;
}

Answer 1

Your player check is wrong,
player[move_finish_i][move_finish_j] == player[move_start_i - 1][move_start_j - 1]
has to be
player[move_finish_i][move_finish_j] == player[move_start_i][move_start_j]
also you should use
return player[move_finish_i][move_finish_j] != player[move_start_i][move_start_j];
The main problem is the check for
move_start_i - 1 == move_finish_i
you have to add a check for the j position!

Answer 2

Insert a
break;
statement at the end of the case ' ': block. Otherwise the default block is executed too if table[move_finish_i][move_finish_j]==' ', which explains why the pawn can move diagonally to blank squares.
Also, the curly brackets after the case and default are not needed. Think of case and default statements as jump labels, code is executed beginning at the first matching case until you leave the switch() {...} block with a break statement (regardless of further 'jump labels').