[C] challenge 13(Unreviewed)

challenge_13/c/karanchawla/README.md

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+```
+Karan Chawla
+Challenge 13
+```
+
+Implemented dynamic arrays and added each digit of the number, created an ```isPalindrome``` method to check for the Palindrome. The method returns ```true``` if the number is a palindrome, else it returns ```flase```.

challenge_13/c/karanchawla/challenge_13.c

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+//Karan Chawla
+//Challenge 13
+
+#include <stdio.h>
+#include <stdlib.h>
+
+// Dynamic Array Definition
+//////////////////////////////////////////////////////////////////////////////////
+typedef struct {
+    int *array;
+    size_t used;
+    size_t size;
+} Array;
+
+void initArray(Array *a, size_t initialSize) 
+{
+    a->array = (int *)malloc(initialSize * sizeof(int));
+    a->used = 0;
+    a->size = initialSize;
+}
+
+void insertArray(Array *a, int element) 
+{
+// a->used is the number of used entries, because a->array[a->used++] updates a->used only *after* the array has been accessed.
+// Therefore a->used can go up to a->size 
+    if (a->used == a->size) 
+    {
+        a->size *= 2;
+        a->array = (int *)realloc(a->array, a->size * sizeof(int));
+    }
+    a->array[a->used++] = element;
+}
+
+void freeArray(Array *a) 
+{
+    free(a->array);
+    a->array = NULL;
+    a->used = a->size = 0;
+}
+/*
+Array a;
+int i;
+initArray(&a, 5);  // initially 5 elements
+for (i = 0; i < 100; i++)
+insertArray(&a, i);  // automatically resizes as necessary
+printf("%d\n", a.array[9]);  // print 10th element
+printf("%d\n", a.used);  // print number of elements
+freeArray(&a);
+*/
+///////////////////////////////////////////////////////////////////////////////////
+
+void isPalindrome(int num)
+{
+    Array a;
+    initArray(&a,1);
+    while(num)
+    {
+        insertArray(&a, num%10);
+        num /= 10;
+    }
+
+    int size = a.used;
+
+    int flag = 1;
+    for(int i=0;i<size/2;i++)
+    {
+        if(a.array[i]==a.array[size-i-1])
+        {
+            flag = 1;
+        }
+        else 
+        {
+            flag = 0;
+            break;
+        }
+    }
+
+    if(flag) printf("True\n");
+    else printf("False\n");
+
+    freeArray(&a);
+}
+
+
+//Driver Program
+int main(void)
+{
+    int num = 1234554321;
+
+    isPalindrome(num);
+
+    return 0;
+}