[C++]异常处理实例-基础版

//头文件

#pragma once
#ifndef SALES_H_
#define SALES_H_
#include <stdexcept>
#include <string>
class Sales {
public:
    enum { MONTHS = 12 };
    class bad_index :public std::logic_error {
    private:
        int bi;
    public:
        explicit bad_index(int ix, const std::string& s = "Index error in Sales object\n");
        int bi_val() const { return bi; }
        virtual ~bad_index() throw() {}
    };
    explicit Sales(int yy = 0);
    Sales(int yy, const double* gr, int n);
    virtual ~Sales() {}
    int Year() const { return year; }
    virtual double operator[](int i) const;
    virtual double& operator[](int i);
private:
    double gross[MONTHS];
    int year;
};
class LabeledSales :public Sales {
public:
    class nbad_index :public Sales::bad_index {
    private:
        std::string lbl;
    public:
        nbad_index(const std::string& lb, int ix, const std::string& s = "Index error in LabelSales object\n");
        const std::string& label_val() const { return lbl; }
        virtual ~nbad_index() throw() {}
    };
    explicit LabeledSales(const std::string& lb = "none", int yy = 0);
    LabeledSales(const std::string& lb, int yy, const double* gr, int n);
    virtual ~LabeledSales() {}
    const std::string& Label() const { return label; }
    virtual double operator[](int i) const;
    virtual double& operator[](int i);
private:
    std::string label;
};
#endif // !SALES_H_

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//方法实现文件

#include "pch.h"
#include "sales.h"
using std::string;
Sales::bad_index::bad_index(int ix, const string& s) :std::logic_error(s), bi(ix) {

}
Sales::Sales(int yy) {
    year = yy;
    for (int i = 0; i < MONTHS; i++)
        gross[i] = 0;
}
Sales::Sales(int yy, const double* gr, int n) {
    year = yy;
    int lim = (n < MONTHS) ? n : MONTHS;
    int i;
    for (i = 0; i < lim; i++)
        gross[i] = gr[i];
    for (; i < MONTHS; i++)
        gross[i] = 0;
}
double Sales::operator[](int i) const {
    if (i < 0 || i >= MONTHS)
        throw bad_index(i);
    return gross[i];
}
double& Sales::operator[](int i) {
    if (i < 0 || i >= MONTHS)
        throw bad_index(i);
    return gross[i];
}
LabeledSales::nbad_index::nbad_index(const string& lb, int ix, const string& s) :Sales::bad_index(ix, s) {
    lbl = lb;
}
LabeledSales::LabeledSales(const string& lb, int yy) : Sales(yy) {
    label = lb;
}
LabeledSales::LabeledSales(const string& lb, int yy, const double* gr, int n) : Sales(yy, gr, n) {
    label = lb;
}
double LabeledSales::operator[](int i) const {
    if (i < 0 || i >= MONTHS)
        throw nbad_index(Label(), i);
    return Sales::operator[](i);
}
double& LabeledSales::operator[](int i) {
    if (i < 0 || i >= MONTHS)
        throw nbad_index(Label(), i);
    return Sales::operator[](i);
}

View Code

//主函数文件

#include "pch.h"
#include <iostream>
#include <string>
#include <cstring>
#include <cctype>
#include <cstdlib>
#include <ctime>
#include <cmath>
#include "sales.h"
using namespace std;

int main(void) {
    double vals[12] = {
        1220,1100,1122,2212,1232,2334,
        2884,2393,3302,2922,3002,3544
    };
    double vals2[12] = {
        12,11,22,21,32,34,
        28,29,33,29,32,35
    };
    Sales sales1(2011, vals, 12);
    LabeledSales sales2("Blogstar", 2012, vals2, 12);
    cout << "First try block:\n";
    try {
        int i;
        cout << "Year = " << sales1.Year() << endl;
        for (i = 0; i < 12; i++) {
            cout << sales1[i] << ' ';
            if (i % 6 == 5)
                cout << endl;
        }
        cout << "Year = " << sales2.Year() << endl;
        cout << "Label = " << sales2.Label() << endl;
        for (i = 0; i <= 12; i++) {
            cout << sales2[i] << ' ';
            if (i % 6 == 5)
                cout << endl;
        }
        cout << "End of try block 1.\n";
    }
    catch (LabeledSales::nbad_index& bad) {
        cout << bad.what();
        cout << "Company: " << bad.label_val() << endl;
        cout << "bad index: " << bad.bi_val() << endl;
    }
    catch (Sales::bad_index& bad) {
        cout << bad.what();
        cout << "bad index: " << bad.bi_val() << endl;
    }
    cout << "\nNext try block:\n";
    try {
        sales2[2] = 37.5;
        sales1[20] = 23345;
        cout << "End of try block 2.\n";
    }
    catch (LabeledSales::nbad_index& bad) {
        cout << bad.what();
        cout << "Company: " << bad.label_val() << endl;
        cout << "bad index: " << bad.bi_val() << endl;
    }
    catch (Sales::bad_index& bad) {
        cout << bad.what();
        cout << "bad index: " << bad.bi_val() << endl;
    }
    cout << "Done\n";
    return 0;
}

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