c++ generate random number

Author: Qianhongbo

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

@@ -0,0 +1,48 @@
+---
+title: C++ generate random number
+date: 2022-09-14 12:27:50
+categories: 
+- Backend
+tags: 
+- c++
+---
+
+```c++
+#include <iostream>
+
+int main() {
+  // initialize random seed
+  srand(time(NULL));
+  // * generate random number
+  for (int i{0}; i < 10; i++) {
+    std::cout << rand() % 10 << " ";
+  }
+  std::cout << "\n";
+
+  // * generate random number in range [a, b), e.g. [3, 6)
+  for (int i{0}; i < 10; i++) {
+    std::cout << rand() % (6 - 3) + 3 << " ";
+  }
+  std::cout << "\n";
+
+  // * generate random number in range [a, b], e.g. [3, 6]
+  for (int i{0}; i < 10; i++) {
+    std::cout << rand() % (6 - 3 + 1) + 3 << " ";
+  }
+  std::cout << "\n";
+
+  // * generate random number in range (a, b], e.g. (3, 6]
+  for (int i{0}; i < 10; i++) {
+    std::cout << rand() % (6 - 3) + 3 + 1 << " ";
+  }
+  std::cout << "\n";
+}
+
+/*
+1 5 6 4 5 2 1 2 1 9
+3 4 3 4 4 5 3 4 5 3
+6 5 4 4 5 3 5 4 3 6
+4 6 4 4 6 5 6 5 4 5
+*/
+```
+