CODEWITHSUNDEEP
c#c
BigOak
BigOak

Reputation: 3

Migrate C to C# problem!

I try to convert C lib to C# and got stuck in this code:

typedef struct _Symbol
{
    unsigned char value;
    unsigned char count;
    unsigned char under;
    unsigned char left, right;
} Symbol;

// [...]

void function(Symbol * symbol) {

...

if (! symbol -> right) break; // So, right is equivalent to bool in C#?

symbol += symbol -> right; // I have no idea what this code will do.

...

}

Please help me out.

Upvotes: 0

Views: 245

Answers (7)

C.J.
C.J.

Reputation: 16111

Try this:

struct Symbol
{
Char value;
int  count; // if your counting, use an integer, not a character
int  under; // not sure that is supposed to represent
int left; 
int right;
}

I'm not sure what you want or need the right and left data members to do. It looks like you wanted to at least increment them, so I left them as integers. In which case you can't just test it using if (symbol.left), but rather you have to use if (symbol.left > 0) etc...

Also C# doesn't use the -> operator, but the . operator exclusively.

In .NET all types cannot just be cast into other types willy nilly. So you can't convert a character (Char in C#) into a bool, or an int.

If you want to keep using C, and still take advantage of .NET you can use the managed compiler /clr and compile all your C Code. But you will have to learn a few extra language keywords, and program a little different.

In general if you are really new to C# and .NET I highly suggest you get two books. The first book is on .NET by Jeffrey Richter (CLR via C#). It's published by Microsoft Press, and is excellent. The other book can or should be C# specific. Charles Petzold has a good introductory book to C# called Programming in the key of C#, that is pretty basic for the language.

Upvotes: 1

Himadri Choudhury
Himadri Choudhury

Reputation: 10353

In C++ any object that has a comparison operator, and can be compared against '0' can be used in an expression in a conditional. If the expression equals 0 then the expression will evaluate to false, otherwise the expression will evaluate to true.

So: if(!symbol->right) will be true if symbol->right is 0.

The following

symbol += symbol->right

is incrementing the symbol pointer by the value stored in symbol->right.

Upvotes: 1

chillitom
chillitom

Reputation: 25686

if (! symbol -> right) break; says if right is zero then break

symbol += symbol -> right; this is performing pointer arithmetic, you'll need to understand why so you can recode it into C#. (assuming symbol is of type Symbol*)

Upvotes: 4

Pablo Santa Cruz
Pablo Santa Cruz

Reputation: 181350

In C# there is no -> operator. To reference a struct member you use . operator. Also, you can't use any expression with if sentences. You must use a proper boolean expression:

if (symbol.right == 0)
    break;

Also, I wouldn't try to convert line-by-line a C program into a C# program. They are based on different paradigms, so you would probably need to learn a little bit of object orientation and how C# manages memory before attempting to translate code.

Upvotes: 5

Daniil
Daniil

Reputation: 637

if (! symbol -> right) break;

I believe this is boolean NOT operation on char in int context. Eg: if (int)right = 0, this is true. Otherwise, it's false.

Upvotes: 0

Jesse Emond
Jesse Emond

Reputation: 7490

The line

if (!symbol->right) break

checks if the character held in the variable right is null (equals '\0'). So, if the character is equal to 0, it will break, otherwise it won't.

Upvotes: 0

manojlds
manojlds

Reputation: 301337

left and right are defined in the struct:

unsigned char left, right;

It is not the wrong, right "right" but left,right right :)

And its equivalent in C# is not bool.

Upvotes: 0

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