update

src/P2822/P2822_prefix.cpp

@@ -19,7 +19,7 @@ static ull k, c[max_n][max_n], prefix[max_n][max_n], t, n, m;
 static void init(){
     c[0][0] = c[1][0] = c[1][1] = 1;
     for(ull i {2};i<max_n;i++){
-        c[i][0]=1;
+        c[i][0]=1; 
         for(ull j{1};j<=i;j++){
             c[i][j] = (c[i-1][j-1] + c[i-1][j])%k;
         }

src/test.cpp

@@ -1,15 +1,76 @@
+#include <type_traits>
+#define NDEBUG
+
 #include <iostream>
-
-using ull = unsigned long long;
-
-ull t;
+#ifndef NDEBUG
+    #include <stdexcept>
+    #include <sstream>
+#endif
 
 #define NV(v)#v<<" : "<<(v)
+using ull = unsigned long long;
+
+#ifdef NDEBUG
+    #define ARR_NDB_NOEXCEPT noexcept
+    #define ARR_NDB_CONSTEXPR constexpr
+#else
+    #define ARR_NDB_CONSTEXPR
+    #define ARR_NDB_NOEXCEPT
+#endif
+
+template<size_t a,size_t b>
+constexpr bool test(){
+    return a>=b;
+}
+
+template<class T, size_t size>
+class Array{
+public:
+private:
+    T arr[size];
+public:
+    ARR_NDB_CONSTEXPR T& operator[](const size_t n)ARR_NDB_NOEXCEPT{
+        #ifndef NDEBUG
+            if(n>=size){
+                std::stringstream ss;
+                ss<<"\nYour [array size] is: "<<size<<"\nBut your [index] is :"<<n<<'\n';
+                throw std::range_error(ss.str());
+            }
+        #endif
+        return arr[n];
+    }
+    ARR_NDB_CONSTEXPR const T& operator[](const size_t n)const ARR_NDB_NOEXCEPT{
+        #ifndef NDEBUG
+            if(n>=size){
+                std::stringstream ss;
+                ss<<"\nYour [array size] is: "<<size<<"\nBut your [index] is :"<<n<<'\n';
+                throw std::range_error(ss.str());
+            }
+        #endif
+        return arr[n];
+    }
+    ARR_NDB_CONSTEXPR operator const T*()const ARR_NDB_NOEXCEPT{
+        return arr;
+    }
+    constexpr bool is_const()const{
+        return true;
+    }
+    constexpr bool is_const(){
+        return false;
+    }
+};
+
+constexpr size_t size {10};
+constexpr Array<ull,size> arr{};
+ull a;
 
 int main(){
-    std::iostream::sync_with_stdio(false), std::cin.tie(nullptr), std::cout.tie(nullptr);
-    
-    std::cout<<NV(t)<<'\n';
-    std::cin>>t;
-    std::cout<<NV(t)<<'\n';
-}   
+    std::cout<<NV(arr)<<'\n';
+    // std::cout<<NV(&arr[size-1])<<'\n'<<NV(&a)<<'\n';
+    // std::cout<<NV(a)<<'\n';
+    // std::cout<<NV(++arr[size])<<'\n';
+    // std::cout<<NV(a)<<'\n';
+    constexpr ull a {arr[size-1]};
+    const constexpr ull *p {arr};
+    std::cout<<NV(a)<<'\n'<<NV(p)<<'\n';
+}