Examples of bit manipulation in CPP

bit-manipulation/elementAppearingOnce.cpp

@@ -0,0 +1,18 @@
+/* Given an array of integers, every element appears twice except for one. Find that single one. */
+
+#include <stdio.h>
+
+int checkNum(int a[], int size) {
+	int ans = 0;
+	for(int i = 0; i < size; i++) {
+		ans^=a[i];
+	}
+	return ans;
+}
+
+int main() {
+	int arr[] = {1,1,2,2,3,4,4,5,5};
+
+	printf("Element appearing once is %d\n", checkNum(arr, sizeof(arr)/sizeof(arr[0])));
+	return 0;
+}

bit-manipulation/numberOfones.cpp

@@ -0,0 +1,23 @@
+/* Write a function that takes an unsigned integer and returns the number of 1 bits it has. */
+
+#include <stdio.h>
+
+int countOnes(int n) {
+	int ans = 0;
+	while(n) {
+		n = n&(n-1);
+		ans++;
+	}
+	return ans;
+}
+
+int main() {
+	printf("Enter a number you want to check the number of 1s in:\n");
+
+	int key;
+	scanf("%d", &key);
+
+	int ans = countOnes(key);
+	printf("%d\n", ans);
+	return 0;
+}