diff --git a/c/p11.c b/c/p11.c
index d6ef183..264549b 100644
--- a/c/p11.c
+++ b/c/p11.c
@@ -13,7 +13,8 @@ int isSameTree(struct TreeNode* p, struct TreeNode* q){
         return 1;
     }
     if(p->val == q->val){
-        return isSameTree(p->left, q->left) || isSameTree(p->right, q->right);
+        if( isSameTree(p->left, q->left) || isSameTree(p->right, q->right))
+            return 1;
     }
     return 0;
 }
diff --git a/c/p13.c b/c/p13.c
index 753cad1..90eeb08 100644
--- a/c/p13.c
+++ b/c/p13.c
@@ -13,7 +13,7 @@ int main(){
     int n = sizeof(a)/sizeof(a[0]);
     int m = sizeof(b)/sizeof(b[0]);
 
-    for(int i=0;i<n;i++);{
+    for(int i=0;i<n;i++){
         printf("%d ", a[i]);
     }
     printf("\n");
diff --git a/c/p14.c b/c/p14.c
index fdd4b97..e50f8ad 100644
--- a/c/p14.c
+++ b/c/p14.c
@@ -21,6 +21,7 @@ int romanToInt(char * s){
     for(int i=0;i<strlen(s)-1;i++){
         if(a[i] < a[i+1]){
             a[i+1] -= a[i];
+            a[i] = 0;
         }
         num += a[i];
     }
diff --git a/c/p5.c b/c/p5.c
index 09475d3..977cf80 100644
--- a/c/p5.c
+++ b/c/p5.c
@@ -6,6 +6,6 @@ void main(){
     int a=10;
     int *ptr = &a;
 
-    *ptr++;
+    (*ptr)++;
     printf("%d", *ptr);
 }
diff --git a/c/p6.c b/c/p6.c
index 2e46837..ccc406e 100644
--- a/c/p6.c
+++ b/c/p6.c
@@ -1,9 +1,10 @@
 //allocating memory to a pointer through a function
 
 #include<stdio.h>
+int x;
 int *fun()
 {
-    int x = 5;
+    x = 5;
     return &x;
 }
 int main()
diff --git a/c/p8.c b/c/p8.c
index 5379851..c5f67e9 100644
--- a/c/p8.c
+++ b/c/p8.c
@@ -5,7 +5,7 @@
 float computeAverage(float* x, size_t* N) {
     float numerator = 0.0;
     float denominator = 0.0;
-    for (size_t i = 0; i < (size_t)N; i++) {
+    for (size_t i = 0; i < (size_t)*N; i++) {
         numerator += x[i];
         denominator++;
     }
diff --git a/c/p9.c b/c/p9.c
index 62ae10a..1867648 100644
--- a/c/p9.c
+++ b/c/p9.c
@@ -9,18 +9,19 @@
  */
 
 #include <stdio.h>
+#include <stdlib.h>
 
 int* filterMultiples(int* arr, int N, int* NOut, int num) {
     int numPrimes = 0;
     *NOut = 0;
     for (int i = 0; i < N; i++) {
         if (arr[i] >= num && arr[i]%num == 0) {
-            *NOut++;
+            (*NOut)++;
         }
     }
     int* multiples = malloc((*NOut)*sizeof(int));
     int idx = 0;
-    for (int i = 0; i < *NOut; i++) {
+    for (int i = 0; i < N; i++) {
         if (arr[i] >= num && arr[i]%num == 0) {
             multiples[idx] = arr[i];
             idx++;
@@ -33,7 +34,8 @@ int main() {
     int arr[10] = {5, 6, 12, 20, 18, 24, 48, 58, 60, 68};
     // Multiples of 6
     int NOut;
-    int* multiples = filterMultiples(arr, 10, &NOut, 6);
+    int* multiples = malloc(100*sizeof(int));
+    multiples = filterMultiples(arr, 10, &NOut, 6);
     for (int i = 0; i < NOut; i++) {
         printf("%i ", multiples[i]);
     }