guys i really need help! else if ..

Quote:

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Originally Posted by AndrewHunter

So, and forgive my ignorance, what exactly does it mean?

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That the declaration of a variable should be delayed to the point where it can be sensibly initialised, as opposed to leaving it uninitialised for several lines, or initialised to a default value that will be overwritten anyway and which could be accidentally used incorrectly before that point. This is not "random", unless you are saying that the structure of the flow of control in your code is "random".

Thnx all! especially to Lasterlight :wink:, it works;)

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This is not "random", unless you are saying that the structure of the flow of control in your code is "random".

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In his defense, I think he was using the term "random" facetiously.

Quote:

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You have to do that anyway when coding with respect to say, C89.

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Not that anyone cares, but the old style is my own personal preference.

Quote:

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Originally Posted by laserlight

That the declaration of a variable should be delayed to the point where it can be sensibly initialised, as opposed to leaving it uninitialised for several lines, or initialised to a default value that will be overwritten anyway and which could be accidentally used incorrectly before that point. This is not "random", unless you are saying that the structure of the flow of control in your code is "random".

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Hmm...something to chew on. Thanks Laser.

The old style is old for a reason. A better style was developed~ there is documented proof that improvements in style formats like declaring variables close to the initial use drives down possible bugs and creates more readable code. The end result is less work which translates to less money being consumed by the project.

The old style is of course important to understand and work with from time to time.

Quote:

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Originally Posted by \007

The old style is old for a reason.

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It is clear and makes sense.

Quote:

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Originally Posted by \007

A better style was developed~ there is documented proof that improvements in style formats like declaring variables close to the initial use drives down possible bugs and creates more readable code.

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Being able to scatter variable declarations randomly throughout your code does not make it a better style:

Code:

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printf( "enter a number: " );
int number;
scanf( "%d", &number );

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That is not better code IMO.

Quote:

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Originally Posted by \007

The old style is of course important to understand and work with from time to time.

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/facepalm

Yes, because declaring variables at the start of a block is so confusing, right?


Quzah.

Quote:

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Originally Posted by quzah

Being able to scatter variable declarations randomly throughout your code does not make it a better style:

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Agreed: ability != style

Quote:

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Originally Posted by quzah

That is not better code IMO.

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Better than what? I'd say that that is not better than:

Code:

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int number;
printf( "enter a number: " );
scanf( "%d", &number );

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Since the printf is related to the scanf and it is unlikely that code that might access number would be inserted in between, so the declaration just before the printf is still sufficiently near first use. However, it is better than:

Code:

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int number;
/* ... several lines of code that does not involve number ... */
printf( "enter a number: " );
scanf( "%d", &number );

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Quote:

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Originally Posted by Justin Chan

Code:

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#include<stdio.h>

int main()
{
     
      char name[30],rcode,D,d,s,S,T,t;
      float rprice,price;
      int days;
     
      printf("------------------------------------------\n\tWELCOME TO LEGEND HOTEL\t\t\n------------------------------------------");
      printf("\nRooms : Delux(D)  Twin Sharing(T)  Single(S)\n\n");
      printf("Enter your name\t\t :");
      gets(name);
      printf("Enter Room code\t\t :");
      scanf("%c", &rcode);
      printf("Enter number of days\t :");
      scanf("%d", &days);
      printf("\n\n------------------------------------------\n\tPAYMENT RECEIPT\t\t\n------------------------------------------\n");
     
     
     
            if(rcode == D || d)
            {rprice = 200.00;
            price = rprice * days;
            printf("Customer Name\t: %s\n", name);
            printf("Room Type\t: Delux\n");
            printf("Room Price\t: %.2f\n", rprice);
            printf("Number of days\t: %d\n", days);
            printf("Bill\t: RM%.2f\n", price);
            }
            else
            if(rcode == T || t)
            {rprice = 170.00;
            price = rprice * days;
            printf("Customer Name\t: %s\n", name);
            printf("Room Type\t: Twin Sharing\n");
            printf("Room Price\t: %.2f\n", rprice);
            printf("Number of days\t: %d\n", days);
            printf("Bill\t: RM%.2f\n", price);
            }
           
            else
            if(rcode == S || s)
            {rprice = 120.00;
            price = rprice * days;
            printf("Customer Name\t: %s\n", name);
            printf("Room Type\t: Single\n");
            printf("Room Price\t: %.2f\n", rprice);
            printf("Number of days\t: %d\n", days);
            printf("Bill\t: RM%.2f\n", price);
            }
            else
            {price = 0;
            price = rprice * days;
            printf("Customer Name\t: %s\n", name);
            printf("Room Type\t: Invalid\n");
            printf("Room Price\t: %.2f\n", rprice);
            printf("Number of days\t: %d\n", days);
            printf("Bill\t: RM%.2f\n", price);
            }
     
     
     
     
     
     
     
     
     
      system("pause");
      getche();
      return 0;
     
     
      }

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First, turn the warning levels on your compiler to their maximum ... then treat every warning as an error to be fixed. You'll be amazed how smart your compiler is about helping you write better code. It should be complaining about uninitialized variables, unused variables and invalid conditional statements...

For example...

Code:

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            if(rcode == D || d)

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... simply isn't going to do what you want it to.

You are obviously wanting to compare the rcode which is typed by the user to find out which letter they've entered. You do that like this...

Code:

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if (rcode == 'D' || rcode == 'd')

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... comparing the value of rcode to character constants, not other variables.

This of course means that your D,d,s,S,T,t variables are unused in the program and can be removed.

Also you have a large amount of redundent code in your program. For example, you only need to display the customer name and number of days once before entering your if/else if sequence, not on every branch of it.

Quote:

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Originally Posted by laserlight

Agreed: ability != style


Better than what? I'd say that that is not better than:

Code:

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int number;
printf( "enter a number: " );
scanf( "%d", &number );

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Since the printf is related to the scanf and it is unlikely that code that might access number would be inserted in between, so the declaration just before the printf is still sufficiently near first use. However, it is better than:

Code:

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int number;
/* ... several lines of code that does not involve number ... */
printf( "enter a number: " );
scanf( "%d", &number );

---

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I feel like you understand what I have been saying. I don't know why Quzah isn't getting it.

For now on, I will just suggest people read a good styles book-- such as Code Complete.

Quote:

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Originally Posted by \007

I don't know why Quzah isn't getting it.

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The ability to scatter variable declarations wherever you feel like in your code as a bad idea. It makes people lazy in that they don't have to think ahead of time about anything they do, and makes your code ugly and harder to read.


Quzah.

Once again, you don't put declarations randomly or scattered at all. You choose the most logical location that is close to the use of it.

The objective is to not have code like this:

Code:

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int main(void)
{
  int i, counter;

  /* 100 lines later */

  counter = 10;
  for(i = 0; i < counter; i++)
    printf("%d\n", i);

  return 0;
}

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Instead we do like this:

Code:

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int main(void)
{
  /* 100 lines later */

  int i, counter = 10;
  for(i = 0; i < counter; i++)
    printf("%d\n", i);

  return 0;
}

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Quote:

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Originally Posted by \007

The objective is to not have code like this:

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I agree, but picking your own places to declare is only legal under C99. Strict C89 code requires that all variables be declared before any instruction (ie, together at the top of a function and no where else). So it does not really make sense to chide people for adhering to that.

However, it is good to let them know that they don't have to, since I think most beginner material is strictly C89 but much or most real programming is C99.

Quote:

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Originally Posted by \007

Once again, you don't put declarations randomly or scattered at all.

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I don't. But you could, and that is the whole reason for my dislike of the ability to do so.

Quote:

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Originally Posted by \007

The objective is to not have code like this:

Code:

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int i, counter;

  /* 100 lines later */

  counter = 10;
  for(i = 0; i < counter; i++)

---

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It is easier for me to locate counter where I expect it (at the top of the current block, or the top of the function) than to have to hunt for it on every single one of those 100 lines.

See, you aren't even doing it right now:

Quote:

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Originally Posted by \007

Instead we do like this:

Code:

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int main(void)
{
  /* 100 lines later */

  int i, counter = 10;
  for(i = 0; i < counter; i++)
    printf("%d\n", i);

  return 0;
}

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You should be doing:

Code:

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for( int i = 0, counter = 10; i < counter; it++ )

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Quzah.

My own opinion is that it's just more organized to keep all the variables located at the top of the block. If this causes confusion or "error because I may have assigned it to something else between here and up there," then that just means I would have to correct and learn from that error.

This is largely about personal preference. I prefer the old ways myself.

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The objective is to not have code like this...

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No, the objective is to have clean, organized code with a consistent style that works the way it should.

One solution that resolves both quzah's consern that variables are hard to find after a block and others' concern that variables are not declared where they are used is to liberally use blocks to mark the exact range where a variable can be accessed.