Question

It was long time since I coded in C and now I can’t even create linked list 🙁 What might be wrong with NodeType structure ?
I even tried this example and still I get error similar to this.

I need to create linked list that would run on linux and windows (without huge modification).

I compile using: cl myFile.c command.

Error message:

Microsoft (R) 32-bit C/C++ Optimizing Compiler Version 16.00.40219.01
for 80×86 Copyright (C) Microsoft Corporation. All rights reserved.

unlock.c unlock.c(46) : error C2275: ‘Node’ : illegal use of this type
as an expression
unlock.c(17) : see declaration of ‘Node’ unlock.c(46) : error C2146: syntax error : missing ‘;’ before identifier ‘a’ unlock.c(46) :
error C2065: ‘a’ : undeclared identifier

Source code:

#include <stdio.h>
#include <windows.h>
#include<stdlib.h>


typedef enum {STABLE, RPUSH, LPUSH} STATUS_TYPE;


typedef struct NodeType
{
    struct NodeType* _left;
    struct NodeType* _right;
    int _value;
}Node;

typedef struct AnchorType
{
    struct Node* _mostLeft;
    struct Node* _mostRight;
    STATUS_TYPE _status;
} Anchor;

Node CreateNode(int data)
{
    Node newNode;
    newNode._value = data;
    newNode._left = NULL;
    newNode._right = NULL;

    return newNode;
}


int main()
{
    Anchor anchor;
    anchor._mostLeft = NULL;
    anchor._mostRight = NULL;
    anchor._status = STABLE;


    Node a; //<-- What might be wrong ?

    return 0;
}

Thanks for help.

Answer 1

Microsoft focuses on C++ compilers, and their C support is decades out of date.

One of the features of the newer C standards that isn’t supported in Microsoft’s compiler is the ability to declare variables in the middle of a function.

Move the declaration to the top, and everything will be ok:

int main()
{
    Anchor anchor;
    Node a; // ok here
    anchor._mostLeft = NULL;
    anchor._mostRight = NULL;
    anchor._status = STABLE;


    //Node a; but not here

    return 0;
}