update

source/_posts/Backend/c++/C-data-types-size.md

@@ -0,0 +1,90 @@
+---
+title: C++ data types size
+date: 2022-10-01 13:09:44
+categories: 
+- c++
+tags: 
+- c++
+---
+
+## Result
+
+```
+the size of bool is: 1
+the size of char is: 1
+the size of short is: 2
+the size of int is: 4
+the size of unsigned int is: 4
+the size of long is: 8
+the size of unsigned long is: 8
+the size of float is: 4
+the size of double is: 8
+the size of long int is: 8
+the size of long long is: 8
+the size of long double is: 8
+the max of short is 32767
+the min of short is -32768
+the max of int is 2147483647
+the min of int is -2147483648
+the max of unsigned int is 4294967295
+the min of unsigned int is 0
+the max of long is 9223372036854775807
+the min of long is -9223372036854775808
+the max of unsigned long is 18446744073709551615
+the min of unsigned long is 0
+the max of long long is 9223372036854775807
+the min of long long is -9223372036854775808
+```
+
+## Code 
+
+``` c++
+#include <iostream>
+#include <limits>
+
+int main() {
+  bool a;
+  char b;
+  short c;
+  int d;
+  unsigned int e;
+  long f;
+  unsigned long g;
+  float h;
+  double i;
+  long int j; // this is the same as long
+  long long k; // for linux x64 long and long long are both 8 bytes
+  long double l;
+
+  std::cout << "the size of bool is: " << sizeof(a) << "\n";
+  std::cout << "the size of char is: " << sizeof(b) << "\n";
+  std::cout << "the size of short is: " << sizeof(c) << "\n";
+  std::cout << "the size of int is: " << sizeof(d) << "\n";
+  std::cout << "the size of unsigned int is: " << sizeof(e) << "\n";
+  std::cout << "the size of long is: " << sizeof(f) << "\n";
+  std::cout << "the size of unsigned long is: " << sizeof(g) << "\n";
+  std::cout << "the size of float is: " << sizeof(h) << "\n";
+  std::cout << "the size of double is: " << sizeof(i) << "\n";
+  std::cout << "the size of long int is: " << sizeof(j) << "\n";
+  std::cout << "the size of long long is: " << sizeof(k) << "\n";
+  std::cout << "the size of long double is: " << sizeof(l) << "\n";
+
+  std::cout << "the max of short is " << std::numeric_limits<short>::max() << "\n";
+  std::cout << "the min of short is " << std::numeric_limits<short>::min() << "\n";
+
+  std::cout << "the max of int is " << std::numeric_limits<int>::max() << "\n";
+  std::cout << "the min of int is " << std::numeric_limits<int>::min() << "\n";
+
+  std::cout << "the max of unsigned int is " << std::numeric_limits<unsigned int>::max() << "\n";
+  std::cout << "the min of unsigned int is " << std::numeric_limits<unsigned int>::min() << "\n";
+
+  std::cout << "the max of long is " << std::numeric_limits<long>::max() << "\n";
+  std::cout << "the min of long is " << std::numeric_limits<long>::min() << "\n";
+
+  std::cout << "the max of unsigned long is " << std::numeric_limits<unsigned long>::max() << "\n";
+  std::cout << "the min of unsigned long is " << std::numeric_limits<unsigned long>::min() << "\n";
+
+  std::cout << "the max of long long is " << std::numeric_limits<long long>::max() << "\n";
+  std::cout << "the min of long long is " << std::numeric_limits<long long>::min() << "\n";
+}
+```

source/_posts/Backend/c++/C-generate-random-number.md

@@ -2,7 +2,7 @@
 title: C++ generate random number
 date: 2022-09-14 12:27:50
 categories: 
-- Backend
+- c++
 tags: 
 - c++
 ---

source/_posts/Backend/c++/Connect-different-classes-in-C.md

@@ -2,7 +2,7 @@
 title: Connect different classes in C++
 date: 2022-02-19 18:04:57
 categories: 
-- Backend
+- c++
 tags: 
 - c++
 ---

source/_posts/Backend/c++/c-多层Switch简化.md

@@ -2,7 +2,7 @@
 title: c++多层Switch简化
 date: 2022-02-10 18:07:40
 categories: 
-- Backend
+- c++
 tags: 
 - c++
 ---

source/_posts/Backend/c++/lambda-expression-in-C.md

@@ -2,7 +2,7 @@
 title: lambda expression in C++
 date: 2022-02-26 16:22:27
 categories: 
-- Backend
+- c++
 tags: 
 - c++
 ---