Create check-prime.md

Author: MihneaMoso

snippets/cpp/basics/check-prime.md

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+---
+title: Check Prime Number
+description: Check if an integer is a prime number
+tags: cpp, number, prime
+author: MihneaMoso
+---
+
+```cpp
+bool is_prime(int n) {
+    if (n < 2) return false;
+    if (n == 2 || n == 3) return true;
+    if (n % 2 == 0) return false;
+    for (int i = 3; i * i <= n; i += 2) {
+        if (n % i == 0) return false;
+    }
+    return true;
+}
+
+// Usage
+#include <iostream>
+
+int main() {
+    std::cout << is_prime(29) << std::endl; // Output: 1
+    return 0;
+}
+```