添加异常处理

base/CMakeLists.txt

@@ -69,4 +69,9 @@ add_executable(tempmemb2 stl/tempmemb2.cpp)
 add_executable(tempparm stl/tempparm.cpp)
 add_executable(frnd2tmp stl/frnd2tmp.cpp)
 add_executable(tmp2tmp stl/tmp2tmp.cpp)
-add_executable(manyfmd stl/manyfmd.cpp)
+add_executable(manyfmd stl/manyfmd.cpp)
+add_executable(error2 exception/error2.cpp)
+add_executable(error3 exception/error3.cpp)
+add_executable(exc_mean exception/exc_mean.cpp)
+add_executable(error5 exception/error5.cpp)
+add_executable(newexcp exception/newexcp.cpp)

base/exception/error2.cpp

@@ -0,0 +1,33 @@
+//
+// Created by nicemoe on 2021/9/5.
+//
+
+#include  <iostream>
+#include <cfloat>
+
+using namespace std;
+
+
+bool hmean(double a, double b, double *ans);
+
+int main() {
+
+    double x, y, z;
+    cout << "Enter two numbers: ";
+    while (cin >> x >> y) {
+        if (hmean(x, y, &z))cout << "Harmonice mean of " << x << " and " << y << " is " << z << endl;
+        else cout <<"One value should not be the negative of the other - try again.\n";
+        cout << "Enter next set of numbers <q to quit>:";
+    }
+    cout << "Bye!\n";
+    return 0;
+}
+
+bool hmean(double a, double b, double *ans) {
+    if (a == -b) {
+        *ans = DBL_MAX;
+        return false;
+    }
+    *ans = 2.0 * a * b / (a + b);
+    return true;
+}

base/exception/error3.cpp

@@ -0,0 +1,35 @@
+//
+// Created by nicemoe on 2021/9/5.
+//
+
+#include  <iostream>
+using namespace std;
+
+
+double hmean(double a, double b);
+
+int main() {
+
+    double x, y, z;
+    cout << "Enter two numbers: ";
+    while (cin >> x >> y) {
+        try {
+            z = hmean(x, y);
+        }catch (const char * s){
+            cout<<s<<endl;
+            cout <<"Enter a new pair numbers: ";
+            continue;
+        }
+        cout << "Harmonice mean of " << x << " and " << y << " is " << z << endl;
+        cout << "Enter next set of numbers <q to quit>:";
+    }
+    cout << "Bye!\n";
+    return 0;
+}
+
+double hmean(double a, double b) {
+    if (a == -b) {
+        throw "bod hmean() arguments: a = -b not allowed";
+    }
+    return 2.0 * a * b / (a + b);
+}

base/exception/error5.cpp

@@ -0,0 +1,95 @@
+//
+// Created by zhuyijun on 2021/9/7.
+//
+
+#include <iostream>
+#include <cmath>
+#include <string>
+#include "exc_mean.h"
+
+using namespace std;
+
+class demo {
+private:
+    string word;
+public:
+    demo(const string &str) {
+        word = str;
+        cout << "demo " << word << " created\n";
+    }
+
+    ~demo() {
+        cout << "demo " << word << " destroyed\n";
+    }
+
+    void show() const {
+        cout << "demo " << word << " lives!\n";
+    }
+};
+
+double hmean(double a, double b);
+
+double gmean(double a, double b);
+
+double means(double a, double b);
+
+int main() {
+    double x, y, z;
+    {
+        demo d1("found in block in main()");
+        cout << "Enter two numbers: ";
+        while (cin >> x >> y) {
+            try {
+                z = means(x, y);
+                cout << "The mean mean of " << x << " and " << y << " is " << z << endl;
+                cout << "Enter next pair: ";
+            } catch (bad_hmean &bh) {
+                bh.mesg();
+                cout << "Try again.\n";
+                continue;
+            } catch (bad_gmean &bg) {
+                cout << bg.mesg();
+                cout << "Values used: " << bg.v1 << " , " << bg.v2 << endl;
+                cout << "Sorry,you don't get to play any more.\n";
+                break;
+            } catch (...) {
+                cout<<"出现异常"<<endl;
+            }
+        }
+        d1.show();
+    }
+    cout << "Bye!\n";
+    cin.get();
+    cin.get();
+    return 0;
+}
+
+double hmean(double a, double b) {
+    if (a == -b)
+        throw bad_hmean(a, b);
+    return 2.0 * a * b / (a + b);
+}
+
+double gmean(double a, double b) {
+    if (a < 0 || b < 0)
+        throw bad_gmean(a, b);
+    return sqrt(a * b);
+}
+
+double means(double a, double b) {
+    double am, hm, gm;
+    demo d2("found in means()");
+    am = (a + b) / 2.0;
+    try {
+        hm = hmean(a, b);
+        hm = gmean(a, b);
+    } catch (bad_hmean &bh) {
+        bh.mesg();
+        cout << "Caught in means()\n";
+        throw;
+    } catch (...) {
+        cout<<"出现异常"<<endl;
+    }
+    d2.show();
+    return (am + hm + gm) / 3.0;
+}

base/exception/exc_mean.cpp

@@ -0,0 +1,48 @@
+//
+// Created by zhuyijun on 2021/9/7.
+//
+
+#include "exc_mean.h"
+#include <cmath>
+
+using namespace std;
+
+double hmean(double a, double b);
+
+double gmean(double a, double b);
+
+int main() {
+    double x, y, z;
+    cout << "Enter two numbers: ";
+    while (cin >> x >> y) {
+        try {
+            z = hmean(x, y);
+            cout << "Harmonic mean of " << x << " and " << y << " is " << z << endl;
+            cout << "Geometric mean of " << x << " and " << y << " is " << gmean(x, y) << endl;
+            cout << "Enter next set of numbers <q to quit>:";
+        } catch (bad_hmean &bh) {
+            bh.mesg();
+            cout << "Try again.\n";
+            continue;
+        } catch (bad_gmean &bg) {
+            cout << bg.mesg();
+            cout << "Values used: " << bg.v1 << " , " << bg.v2 << endl;
+            cout << "Sorry,you don't get to play any more.\n";
+            break;
+        }
+    }
+    cout << "Bye!\n";
+    return 0;
+}
+
+double hmean(double a, double b) {
+    if (a == -b)
+        throw bad_hmean(a, b);
+    return 2.0 * a * b / (a + b);
+}
+
+double gmean(double a, double b) {
+    if (a < 0 || b < 0)
+        throw bad_gmean(a, b);
+    return sqrt(a * b);
+}

base/exception/exc_mean.h

@@ -0,0 +1,33 @@
+//
+// Created by zhuyijun on 2021/9/7.
+//
+
+#ifndef BASE_EXC_MEAN_H
+#define BASE_EXC_MEAN_H
+#include <iostream>
+
+class bad_hmean {
+private:
+    double v1;
+    double v2;
+public:
+    bad_hmean(double a=0,double b=0):v1(a),v2(b){}
+    void mesg();
+
+};
+inline void bad_hmean::mesg() {
+    std::cout<<"hmean("<<v1<<", "<<v2<<") : " <<"invalid arguments:a = -b\n";
+}
+
+class bad_gmean{
+public:
+    double v1;
+    double v2;
+    bad_gmean(double a=0,double b=0):v1(a),v2(b){}
+    const char * mesg();
+};
+
+inline const char * bad_gmean::mesg() {
+    return "gmean() arguments should be >= 0\n";
+}
+#endif //BASE_EXC_MEAN_H

base/exception/newexcp.cpp

@@ -0,0 +1,30 @@
+//
+// Created by zhuyijun on 2021/9/7.
+//
+
+#include <iostream>
+#include <new>
+#include <cstdlib>
+
+using namespace std;
+
+struct Big{
+    double stuff[20000];
+};
+int main() {
+    Big * pb;
+    try {
+        cout <<"Trying to get a big block of memory:\n";
+        pb = new Big[100000];
+        cout<<"Got past the new request:\n";
+    }catch (bad_alloc & ba){
+        cout <<"Caught the exception\n";
+        cout <<ba.what()<<endl;
+    }
+    cout <<"Memory successfully allocated\n";
+    pb[0].stuff[0] = 4;
+    cout <<  pb[0].stuff[0] << endl;
+    delete []pb;
+    return 0;
+}
+