tmp

15/04/f.cpp

@@ -0,0 +1,12 @@
+#include <string>
+#include <iostream>
+#include <functional>
+
+using namespace std;
+
+int main() {
+    string s = "+03.14e-03"s;
+    cout << "字符串: " << s << endl;
+    float f = stof(s);
+    cout << "浮点数: " << f << endl;
+}

15/05/a.cpp

@@ -1,9 +1,9 @@
-#include <iostream>
 #include <string>
+#include <iostream>
+#include <iomanip>
 
 using namespace std;
 
 int main() {
-    cout << string("hello\0cpp") << endl;
-    cout << string("hello\0cpp", 9) << endl;
+    cout << "十六进制：" << hex << 42 << endl;
 }

15/05/b.cpp

@@ -1,22 +1,13 @@
 #include <string>
-#include <string_view>
 #include <iostream>
+#include <sstream>
+#include <iomanip>
 
 using namespace std;
 
 int main() {
-    string s1 = "hello";
-    string s2 = s1;         // 深拷贝
-    string_view sv1 = s1;   // 弱引用
-    string_view sv2 = sv1;  // 浅拷贝
-    cout << "s1=" << s1 << endl;
-    cout << "s2=" << s2 << endl;
-    cout << "sv1=" << sv1 << endl;
-    cout << "sv2=" << sv2 << endl;
-    s1[0] = 'B';
-    cout << "修改s1后" << endl;
-    cout << "s1=" << s1 << endl;
-    cout << "s2=" << s2 << endl;
-    cout << "sv1=" << sv1 << endl;
-    cout << "sv2=" << sv2 << endl;
+    stringstream ss;
+    ss << "十六进制：" << hex << 42;
+    string s = ss.str();
+    cout << s << endl;
 }

15/05/c.cpp

@@ -0,0 +1,17 @@
+#include <string>
+#include <iostream>
+#include <sstream>
+#include <iomanip>
+
+using namespace std;
+
+int main() {
+    string s = "42yuan"s;
+    stringstream ss(s);
+    int num;
+    ss >> num;
+    string unit;
+    ss >> unit;
+    cout << "数字：" << num << endl;
+    cout << "单位：" << unit << endl;
+}

15/07/a.cpp

@@ -0,0 +1,9 @@
+#include <iostream>
+#include <string>
+
+using namespace std;
+
+int main() {
+    cout << string("hello\0cpp") << endl;
+    cout << string("hello\0cpp", 9) << endl;
+}

15/07/b.cpp

@@ -0,0 +1,22 @@
+#include <string>
+#include <string_view>
+#include <iostream>
+
+using namespace std;
+
+int main() {
+    string s1 = "hello";
+    string s2 = s1;         // 深拷贝
+    string_view sv1 = s1;   // 弱引用
+    string_view sv2 = sv1;  // 浅拷贝
+    cout << "s1=" << s1 << endl;
+    cout << "s2=" << s2 << endl;
+    cout << "sv1=" << sv1 << endl;
+    cout << "sv2=" << sv2 << endl;
+    s1[0] = 'B';
+    cout << "修改s1后" << endl;
+    cout << "s1=" << s1 << endl;
+    cout << "s2=" << s2 << endl;
+    cout << "sv1=" << sv1 << endl;
+    cout << "sv2=" << sv2 << endl;
+}