int infixToPostfix(char* exp)
{
int i,k;
struct Stack* stack = createStack(strlen(exp));
if (!stack)
return -1;
for ( i=0, k=-1; exp[i]; ++i)
{
if(isOperand(exp[i]))
exp[++k] = exp[i];
else if (exp[i]== '(')
push(stack,exp[i]);
else if (exp[i]== ')')
{
while (!isEmpty(stack) && peek(stack)!='(' )
exp[++k]=pop(stack);
if (!isEmpty(stack) && peek(stack))
return -1;
else
pop(stack);
}
else
{
while (!isEmpty(stack) && Precedence(exp[i]) <= Precedence(peek(stack)))
exp[++k]=pop(stack);
push(stack,exp[i]);
}
}
while (isEmpty(stack))
exp[++k]=pop(stack);
exp[++k]= '\0';
printf("%s",exp);
}
static double Reduce( PBIOP Exp )
{
PBIOP Right;
double dRet = 0;
if( Exp->Operator[0] == 0 )
{
dRet = Exp->Left;
free( (void *) Exp );
return dRet;
}
if( Exp->Right->Operator[0] && Precedence( Exp ) >= Precedence( Exp->Right ) )
{
Right = Exp->Right;
Exp->Right = BiOp();
Exp->Right->Left = Right->Left;
Right->Left = Reduce( Exp );
return Reduce( Right );
}
//printf( "Operator: %s Left: %i Right: %i\n", Exp->Operator, (int) Exp->Left, (int) Reduce( Exp->Right ) );
switch( Exp->Operator[0] )
{
case '+':
dRet = Exp->Left + Reduce( Exp->Right );
break;
case '-':
dRet = Exp->Left - Reduce( Exp->Right );
break;
case '*':
dRet = Exp->Left * Reduce( Exp->Right );
break;
case '/':
dRet = Exp->Left / Reduce( Exp->Right );
break;
case '&':
if( Exp->Operator[1] )
{
if( Exp->Left )
{
dRet = Reduce( Exp->Right ) ? 1 : 0;
}
else
{
dRet = 0;
}
}
else
{
dRet = (long) Exp->Left & (long) Reduce( Exp->Right );
}
break;
case '|':
if( Exp->Operator[1] )
{
if( Exp->Left )
{
dRet = 1;
}
else
{
dRet = Reduce( Exp->Right ) ? 1 : 0;
}
}
else
{
dRet = (long) Exp->Left | (long) Reduce( Exp->Right );
}
break;
case '=':
dRet = (long) Exp->Left == (long) Reduce( Exp->Right );
break;
case '!':
dRet = (long) Exp->Left != (long) Reduce( Exp->Right );
break;
case '<':
if( Exp->Operator[1] )
{
dRet = (long) Exp->Left <= (long) Reduce( Exp->Right );
}
else
{
dRet = (long) Exp->Left < (long) Reduce( Exp->Right );
}
break;
case '>':
if( Exp->Operator[1] )
{
dRet = (long) Exp->Left >= (long) Reduce( Exp->Right );
}
else
{
dRet = (long) Exp->Left > (long) Reduce( Exp->Right );
}
break;
}
free( (void *) Exp );
return dRet;
}
void Expr::ReduceAndPush(Expr *n) {
while(Precedence(n) <= Precedence(TopOperator())) {
Reduce();
}
PushOperator(n);
}
