fix some bug

README.md

@@ -4,7 +4,7 @@ C++ Primer Plus 6th answers (by **PytLab**)
 
 C++ Primer Plus(第六版) 编程练习答案(全部本人所写，仅供参考)
 
-###Table of Content
+### Table of Content
 
  - [第三章 处理数据](https://github.com/PytLab/Cpp-Primer-Plus/tree/master/ch03)
  - [第四章 复合类型](https://github.com/PytLab/Cpp-Primer-Plus/tree/master/ch04)

ch07/7_9.cpp

@@ -52,7 +52,7 @@ int getinfo(student * pstu, int n)
         cout << "fullname: ";
         // detect blank line
         cin.getline(pt->fullname, Slen);
-        if(!pt->fullname)
+        if(!*pt->fullname)
             break;
         cout << "hobby: ";
         cin.getline(pt->hobby, Slen);

ch11/11_1/randwalk.cpp

@@ -20,7 +20,11 @@ int main()
     // write to file
     ofstream fout;
     fout.open("walk.txt");
-
+    if (!fout.is_open()) {
+        cout << "Could not write to file \n";
+        cout << "Program terminating.\n";
+        exit(EXIT_FAILURE);
+    }
     cout << "Enter target distance (q to quit): ";
     while (cin >> target)
     {
@@ -29,29 +33,37 @@ int main()
             break;
 
         // write to file
-        fout << "Target Distance: " << target << ", ";
-        fout << "Step Size: " << dstep << endl;
 
+        fout << "Target Distance: " << target << ", Step Size: " << dstep << endl
+             << steps << ": " << result << endl;
         while (result.magval() < target)
         {
             direction = rand() % 360;
             step.reset(dstep, direction, Vector::POL);
             result = result + step;
-            fout << steps << ": " << result << endl;
             steps++;
+            fout << steps << ": " << result << endl;
         }
         cout << "After " << steps << " steps, the subject "
             "has the following location:\n";
         cout << result << endl;
+        fout <<  "After " << steps
+             << " steps, the subject "
+             "has the following location:\n" << result << endl;
         result.polar_mode();
         cout << " or\n" << result << endl;
         cout << "Average outward distance per step = "
-            << result.magval()/steps << endl;
+             << result.magval()/steps << endl;
+        fout << " or\n"
+             << result << endl
+             << "Average outward distance per step = " << result.magval() / steps
+             << endl;
         steps = 0;
         result.reset(0.0, 0.0);
         cout << "Enter target distance (q to quit): ";
     }
     cout << "Bye!\n";
+    fout.close();
 
     return 0; 
 }