save code

old/lession4.cpp

@@ -0,0 +1,10 @@
+#include <iostream>
+#include <cstdlib>
+#include <ctime>
+
+int main() {
+    std::srand(std::time(nullptr));
+    int r = std::rand() % 101;
+    std::cout << " 随机数 " << r << "\n";
+    return 0;
+}