malloc struct node array

Code:

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if((relation[i] =(Tnode)malloc(sizeof(TableNode)))==NULL)//allocate memory
            {
              printf("Failled to allocate memory.\n"); fflush(stdout); exit(1);
            }

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TableNode relation[100];
typedef sturct node TableNode;
typedef TableNode * Tnode;
how u malloc struct node []? Mine is wrong.

Quote:

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Originally Posted by p595285902

TableNode relation[100];

how u malloc struct node []? Mine is wrong.

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You don't. "Relation" is not a pointer array.

So u can't store information in array only the node that array points to ?

If relation was:

Code:

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Tnode relation[100];

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...then it would be an array of pointers to your struct and you could then dynamically allocate memory to those individual array cells (pointers).

You can store information in an array of struct nodes (TableNodes), you just don't need to do any dynamic allocation since you can simply treat each cell of the array as if it were already a struct node.

[edit]Avoid casting the return value from the malloc call. The returned void pointer can be safely assigned without it.[/edit]

Code:

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if((newPtr=(Tnode)malloc(sizeof(TableNode)))==NULL)//allocate memory
            {
              printf("Failled to allocate memory.\n"); fflush(stdout); exit(1);
            }
          strcpy(newPtr->name,rel);//set relation's name
          relation[i]=*newPtr;

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is this what you mean?

Do you want an array of pointers to struct node or do you want an array of struct node. There is little reason for you to do things the way you are doing them. Either have an array of pointers and dynamically allocate memory to those pointers or have an array of structs and don't do any dynamic memory allocation.

What you are doing above looks like you want to keep using an array of structs but then you are doing some dynamic memory allocation and then copying the allocated struct to the array of struct... which is kind of pointless. It would help if you had (re)posted the declaration of relation array otherwise we are left scratching our heads guessing what it looks like since you're only giving us a part of the complete picture and we are assuming a certain declaration that may or may not be correct.