iamrkcheers iamrkcheers - 1 month ago 9
C Question

Error : Conflicting types for 'remove'

I am getting an error "Conflicting types for 'remove'" at the line where I define my remove function.
Most cases for this error occur whilst calling a function before its declaration.
However, I'm making calls to my remove() in the main function, whilst having defined it beforehand.
Then, why the error ?!?

#include<stdio.h>
#include<stdbool.h>

struct node
{
int data;
struct node* left;
struct node* right;
};

struct node* newNode(int x)
{
struct node* temp=(struct node*)malloc(sizeof(struct node));
temp->data=x;
temp->left=NULL;
temp->right=NULL;
return temp;
}

struct node* insert(struct node* root,int x)
{
if (root==NULL)
root=newNode(x);
else if (x<=root->data)
root->left=insert(root->left,x);
else
root->right=insert(root->right,x);
return root;
}

struct node* remove(struct node* root,int x)
{
if (root==NULL)
printf("Node not found !\n");
else if (x==root->data)
{
struct node* temp=root;
root=NULL;
free(temp);
printf("Node removed !\n");
}
else if (x<=root->data)
root->left=remove(root->left,x);
else
root->right=remove(root->right,x);
return root;
}

bool search(struct node* root,int x)
{
if (root==NULL)
return false;
else if (x==root->data)
return true;
else if (x<=root->data)
return search(root->left,x);
else
return search(root->right,x);
}

void main()
{
struct node* root=NULL;
root=insert(root,20);
root=remove(root,10);
root=insert(root,8);
root=remove(root,10);
root=insert(root,22);
root=remove(root,22);
root=insert(root,21);
root=remove(root,10);
root=insert(root,12);
root=remove(root,12);
root=insert(root,16);
root=remove(root,10);
root=insert(root,0);
root=remove(root,10);
root=insert(root,11);
root=remove(root,10);
root=remove(root,11);
printf(search(root,10)?"Found\n":"Not Found\n");
printf(search(root,20)?"Found\n":"Not Found\n");
printf(search(root,11)?"Found\n":"Not Found\n");
printf(search(root,17)?"Found\n":"Not Found\n");
}

Answer

When compiling your code, I get this:

/tmp/x1.c:32: error: conflicting types for ‘remove’
/usr/include/stdio.h:154: error: previous declaration of ‘remove’ was here

As you can see, there is a function declared in stdio.h named remove. That conflicts with the definition you have.

You'll need to rename your function so it doesn't clash with the definition in stdio.h.

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