한빛미디어

계산기가 계산도 제대로 안되고 곱셈나눗셈의 우선순위를 바꿔봐도

중복괄호를 쓰면 이상해져서 나름대로 메모장에 써가면서 코드를 이리저리 고쳐보다가 아래 코드로

변경 하니까 우선순위도 중복괄호 적용도 제대로 되네요.

근데 제가 바꾸긴했지만 복잡하기도하고 어거지로 바꾼거같아서 정리가 잘 안되는거같아서요.

이 부분에 대해서 정리좀 부탁드려도될까요.



변경전:

int IsPrior( char OperatorInStack, char OperatorInToken )
{
    return ( GetPriority(OperatorInStack, 1) > GetPriority(OperatorInToken, 0) );
}

변경후:

int IsPrior( char OperatorInStack, char OperatorInToken )
{
    return ( GetPriority(OperatorInStack, 0) >= GetPriority(OperatorInToken, 1) );   // 리턴시 >부분을 >=로 바꾸고
}                                                                                                                   왼쪽괄호의 우선순위 변경
                                                                                                                    (우선순위코드에서도변경가능.)
변경전:
void GetPostfix( char* InfixExpression, char* PostfixExpression )
{
    LinkedListStack* Stack;

    char Token[32];
    int  Type = -1;
    unsigned int Position = 0;
    unsigned int Length = strlen( InfixExpression );

    LLS_CreateStack(&Stack);

    while ( Position < Length )
    {
        Position += GetNextToken( &InfixExpression[Position], Token, &Type );

        if ( Type == OPERAND )
        {
            strcat( PostfixExpression, Token );
            strcat( PostfixExpression, " " );
        }
        else if ( Type == RIGHT_PARENTHESIS )
        {              
            while ( !LLS_IsEmpty(Stack) )
            {
                Node* Popped = LLS_Pop( Stack );

                if ( Popped->Data[0] == LEFT_PARENTHESIS )
                {
                    LLS_DestroyNode( Popped );
                    break;
                }
                else
                {
                    strcat( PostfixExpression, Popped->Data );          
                    LLS_DestroyNode( Popped );
                }
            }
        }
        else
        {
            while ( !LLS_IsEmpty( Stack ) &&
                    !IsPrior( LLS_Top( Stack )->Data[0], Token[0] ) )
            {
                Node* Popped = LLS_Pop( Stack );

                if ( Popped->Data[0] != LEFT_PARENTHESIS )
                    strcat( PostfixExpression, Popped->Data );
                
                LLS_DestroyNode( Popped );
            }
            
            LLS_Push( Stack, LLS_CreateNode( Token ) );
        }
    }

    while ( !LLS_IsEmpty( Stack) )
    {
        Node* Popped = LLS_Pop( Stack );

        if ( Popped->Data[0] != LEFT_PARENTHESIS )
            strcat( PostfixExpression, Popped->Data );
        
        LLS_DestroyNode( Popped );
    }

    LLS_DestroyStack(Stack);
}

변경후:
void GetPostfix( char* InfixExpression, char* PostfixExpression )
{
    LinkedListStack* Stack;

    char Token[32];
    int  Type = -1;
    unsigned int Position = 0;
    unsigned int Length = strlen( InfixExpression );

    LLS_CreateStack(&Stack);

    while ( Position < Length )
    {
        Position += GetNextToken( &InfixExpression[Position], Token, &Type );

        if ( Type == OPERAND )
        {
            strcat( PostfixExpression, Token );
            strcat( PostfixExpression, " " );
        }
        else if ( Type == RIGHT_PARENTHESIS )
        {              
            while ( !LLS_IsEmpty(Stack) )
            {
                Node* Popped = LLS_Pop( Stack );

                if ( Popped->Data[0] == LEFT_PARENTHESIS )
                {
                    LLS_DestroyNode( Popped );
                    break;
                }
                else
                {
                    strcat( PostfixExpression, Popped->Data );          
                    LLS_DestroyNode( Popped );
                }
            }
        }
        else
        {
            while ( !LLS_IsEmpty( Stack ) &&
                    IsPrior( LLS_Top( Stack )->Data[0], Token[0] ) )                  // IsPrior의 앞 !를 삭제
            {
                Node* Popped = LLS_Pop( Stack );

                if ( Popped->Data[0] != LEFT_PARENTHESIS )
                    strcat( PostfixExpression, Popped->Data );
                
                LLS_DestroyNode( Popped );
            }
            
            LLS_Push( Stack, LLS_CreateNode( Token ) );
        }
    }

    while ( !LLS_IsEmpty( Stack) )
    {
        Node* Popped = LLS_Pop( Stack );

        if ( Popped->Data[0] != LEFT_PARENTHESIS )
            strcat( PostfixExpression, Popped->Data );
        
        LLS_DestroyNode( Popped );
    }

    LLS_DestroyStack(Stack);
}