Language: C

int main(){
  int n, i, x;
  char com[20];
  scanf("%d", &n);
  
  for ( i = 0; i < n; i++ ){
    scanf("%s", com);
    if ( com[0] == 'f' ){
      scanf("%d", &x);
      Node t = treeSearch(root, x);
      
      if ( t != NIL ) printf("yes\n");
      
      else printf("no\n");
    } 
     if ( com[0] == 'i' ){
       scanf("%d", &x);
       insert(x);
     }
     else if ( com[0] == 'p' ){
       inorder(root);
       printf("\n");
       preorder(root);
       printf("\n");
     }
     else if ( com[0] == 'd' ){
       scanf("%d", &x);
       treeDelete(treeSearch(root, x));
     }
  }
  
  return 0;
}

Compiler output:
main.c: In function 'main':
main.c:4:3: error: implicit declaration of function 'scanf' [-Wimplicit-function-declaration]
    4 |   scanf("%d", &n);
      |   ^~~~~
main.c:1:1: note: include '<stdio.h>' or provide a declaration of 'scanf'
  +++ |+#include <stdio.h>
    1 | int main(){
main.c:4:3: warning: incompatible implicit declaration of built-in function 'scanf' [-Wbuiltin-declaration-mismatch]
    4 |   scanf("%d", &n);
      |   ^~~~~
main.c:4:3: note: include '<stdio.h>' or provide a declaration of 'scanf'
main.c:10:7: error: unknown type name 'Node'
   10 |       Node t = treeSearch(root, x);
      |       ^~~~
main.c:10:16: error: implicit declaration of function 'treeSearch' [-Wimplicit-function-declaration]
   10 |       Node t = treeSearch(root, x);
      |                ^~~~~~~~~~
main.c:10:27: error: 'root' undeclared (first use in this function)
   10 |       Node t = treeSearch(root, x);
      |                           ^~~~
main.c:10:27: note: each undeclared identifier is reported only once for each function it appears in
main.c:12:17: error: 'NIL' undeclared (first use in this function)
   12 |       if ( t != NIL ) printf("yes\n");
      |                 ^~~
main.c:12:23: error: implicit declaration of function 'printf' [-Wimplicit-function-declaration]
   12 |       if ( t != NIL ) printf("yes\n");
      |                       ^~~~~~
main.c:12:23: note: include '<stdio.h>' or provide a declaration of 'printf'
main.c:12:23: warning: incompatible implicit declaration of built-in function 'printf' [-Wbuiltin-declaration-mismatch]
main.c:12:23: note: include '<stdio.h>' or provide a declaration of 'printf'
main.c:14:12: warning: incompatible implicit declaration of built-in function 'printf' [-Wbuiltin-declaration-mismatch]
   14 |       else printf("no\n");
      |            ^~~~~~
main.c:14:12: note: include '<stdio.h>' or provide a declaration of 'printf'
main.c:18:8: error: implicit declaration of function 'insert' [-Wimplicit-function-declaration]
   18 |        insert(x);
      |        ^~~~~~
main.c:21:8: error: implicit declaration of function 'inorder' [-Wimplicit-function-declaration]
   21 |        inorder(root);
      |        ^~~~~~~
main.c:22:8: warning: incompatible implicit declaration of built-in function 'printf' [-Wbuiltin-declaration-mismatch]
   22 |        printf("\n");
      |        ^~~~~~
main.c:22:8: note: include '<stdio.h>' or provide a declaration of 'printf'
main.c:23:8: error: implicit declaration of function 'preorder' [-Wimplicit-function-declaration]
   23 |        preorder(root);
      |        ^~~~~~~~
main.c:28:8: error: implicit declaration of function 'treeDelete' [-Wimplicit-function-declaration]
   28 |        treeDelete(treeSearch(root, x));
      |        ^~~~~~~~~~