bug:connect函数在处理插入已存在连接时的业务逻辑错误

homework5/GraphExceptions/InsertExistedConnectException.h

@@ -0,0 +1,26 @@
+// 这是一个异常，当用户尝试插入已存在的连接时抛出
+
+#ifndef INSERTEXISTEDCONNECTEXCEPTION_H
+#define INSERTEXISTEDCONNECTEXCEPTION_H
+#include <exception>
+#include <string>
+
+
+class InsertExistedConnectException : public std::exception{
+private:
+    std::string message;
+public:
+    InsertExistedConnectException():message("You input id is out of range"){}
+    InsertExistedConnectException(const std::string& msg) : message(msg) {}
+    InsertExistedConnectException(const std::string& msg,int errCode):message(msg+" Err code: "+std::to_string(errCode)){}
+
+    virtual ~InsertExistedConnectException() noexcept {}
+    virtual const char* what() const noexcept override {
+        return message.c_str();
+    }
+
+};
+
+
+
+#endif //INSERTEXISTEDCONNECTEXCEPTION_H