diff --git a/DS/C/Lab/Shortcodes/polyadds.c b/DS/C/Lab/Shortcodes/polyadds.c
new file mode 100644
index 0000000..b448972
--- /dev/null
+++ b/DS/C/Lab/Shortcodes/polyadds.c
@@ -0,0 +1,50 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+typedef struct p { int c, e; struct p *n; } *P;
+
+P new_p(int c, int e) {
+    P t = malloc(sizeof(struct p));
+    t->c = c; t->e = e; t->n = NULL; return t;
+}
+
+void insert_end(int c, int e, P *h) {
+    P t = new_p(c, e);
+    if (!*h) *h = t;
+    else { P cur = *h; while (cur->n) cur = cur->n; cur->n = t; }
+}
+
+void attach(int c, int e, P *r) {
+    (*r)->n = new_p(c, e); *r = (*r)->n;
+}
+
+P poly_add(P A, P B) {
+    P r = new_p(0, 0), C = r;
+    while (A && B) {
+        int d = A->e - B->e;
+        if (d < 0) { attach(B->c, B->e, &r); B = B->n; }
+        else if (d > 0) { attach(A->c, A->e, &r); A = A->n; }
+        else { int s = A->c + B->c; if (s) attach(s, A->e, &r); A = A->n; B = B->n; }
+    }
+    for (; A; A = A->n) attach(A->c, A->e, &r);
+    for (; B; B = B->n) attach(B->c, B->e, &r);
+    P t = C; C = C->n; free(t); return C;
+}
+
+void print_poly(P p) {
+    if (!p) return;
+    printf("%dx^%d", p->c, p->e);
+    for (p = p->n; p; p = p->n) printf(" + %dx^%d", p->c, p->e);
+    printf("\n");
+}
+
+int main() {
+    P A = NULL, B = NULL;
+    insert_end(3, 3, &A); insert_end(4, 2, &A); insert_end(1, 0, &A);
+    printf("1st Polynomial: "); print_poly(A);
+    insert_end(6, 4, &B); insert_end(5, 2, &B); insert_end(4, 1, &B);
+    printf("2nd Polynomial: "); print_poly(B);
+    P C = poly_add(A, B);
+    printf("Added Polynomial: "); print_poly(C);
+    return 0;
+}
diff --git a/DS/C/Lab/Shortcodes/recurtree.c b/DS/C/Lab/Shortcodes/recurtree.c
new file mode 100644
index 0000000..52126e8
--- /dev/null
+++ b/DS/C/Lab/Shortcodes/recurtree.c
@@ -0,0 +1,34 @@
+#include<stdio.h>
+#include<stdlib.h>
+#define M 100
+
+typedef struct N *P;
+typedef struct N{int d;P l,r;}N;P root;
+
+int t=-1;P stk[M];
+P cn(int v){P n=malloc(sizeof(N));n->d=v;n->l=n->r=NULL;return n;}
+
+P cr(P r,int v){
+    if(!r)return cn(v);
+    if(v<r->d)r->l=cr(r->l,v);
+    else if(v>r->d)r->r=cr(r->r,v);
+    return r;
+}
+
+void po(P r){if(r){po(r->l);po(r->r);printf("%d ",r->d);}}
+void pr(P r){if(r){printf("%d ",r->d);pr(r->l);pr(r->r);}}
+void io(P r){if(r){io(r->l);printf("%d ",r->d);io(r->r);}}
+
+int main(){
+    root=cr(root,6);
+    root=cr(root,4);
+    root=cr(root,83);
+    root=cr(root,25);
+    root=cr(root,42);
+
+    printf("Binary Tree (In-Order): ");io(root);puts("");
+    printf("Binary Tree (Pre-Order): ");pr(root);puts("");
+    printf("Binary Tree (Post-Order): ");po(root);puts("");
+
+    return 0;
+}