fix a snippets and update another.

snippets/cpp/bit-manipulation/find-non-repeating-number.md

@@ -6,9 +6,11 @@ author: ashukr07
 ---
 
 ```cpp
+#include <vector>
+
 int find_non_repeating(const std::vector<int>& nums) {
     int result = 0;
-    for (int num : nums) {
+    for (const int num : nums) {
         result ^= num;
     }
     return result;
@@ -17,4 +19,4 @@ int find_non_repeating(const std::vector<int>& nums) {
 // Usage:
 std::vector<int> nums = {4, 1, 2, 1, 2};
 find_non_repeating(nums); // Returns: 4
-```
+```

snippets/cpp/math-and-numbers/binary-to-unsigned-integer-conversion.md

@@ -0,0 +1,26 @@
+---
+title: Binary to Unsigned Integer Conversion
+description: Converts a binary number represented as a string to its decimal equivalent.
+tags: binary, conversion, c++20
+author: ashukr07
+contributor: majvax
+---
+
+```cpp
+#include <string>
+#include <bitset>
+#include <stdexcept>
+
+template <std::unsigned_integral T>
+T binary_to_uintegral(const std::string& binary) {
+    if (binary.size() > sizeof(T) * 8)
+        throw std::invalid_argument("binary string is too long");
+    return static_cast<T>(std::bitset<sizeof(T) * 8>(binary).to_ullong());
+}
+
+// Usage:
+std::string binary(64, '1'); // Binary 8 bytes long with all bits set to 1
+binary_to_uintegral<unsigned long long>(binary); // Returns: 18446744073709551615
+binary_to_uintegral<long long>(binary); // Compiles error: signed/unsigned mismatch
+binary_to_uintegral<unsigned long long>(std::string(65, '1')); // Throws: std::invalid_argument
+```