帮满修改下！ - 编程论坛

#2

最近不在2010-03-12 16:08

我想用模板函数，然后输出数组的和，编译有一个错误，帮改下

#3

chengwen10162010-03-12 18:48

回复楼主最近不在

修改如下:

#include<iostream>
using namespace std;

template<class any>
showarray(any array[],int n);

template<class any>
showarray(any *array[],int n);

struct debts
{
    char name[50];
    double amount;
};

int main(void)
{
    int things[6]={13,31,103,301,310,130};
    struct debts mr_e[3]=
    {
        {"I am A",240.0},
        {"I am B",120.0},
        {"I am C",150.0}
    };
    double *pd[3];

    for(int i=0;i<3;i++)
    pd[i]=&mr_e[i].amount;

    cout<<"listing mr_e's counts of things: \n";
    showarray(things,6);
    cout<<"listing mr_e's debts: \n";
    showarray(*pd,3);  // 这里传参数要传 *pd
    return 0;
}

template<class any>
showarray(any array[],int n)
{
    float sum = 0;     // 要赋初值 0, 否则得不到正确结果的,因为 sum 的初值为一个任意数
    cout<<"template A\n";
    for(int i=0;i<n;i++)
        sum+=array[i];
    cout<<"sum="<<sum;
    cout<<endl;
    return sum;
}

template<class any>
showarray(any *array[],int n)
{
    float sum = 0;   // 要赋初值 0
    cout<<"template A\n";
    for(int i=0;i<n;i++)
        sum+=*array[i];
    cout<<"sum="<<sum;
    cout<<endl;
    return sum;
}

#4

ltyjyufo2010-03-12 20:42

同意3楼的修改，就是在showarray(any array[],int n)和showarray(any *array[],int n)函数这里，楼主应该指明他的返回类型，这样写规范一定嘛。。。。。。。

#5

最近不在2010-03-13 00:00

谢谢2楼了，3楼貌似看跑了，呵呵

#6

最近不在2010-03-13 00:03

我还想问下，就是第二个的和求的不对，再该怎么改了？

#7

杨三星2010-03-13 09:48

呵呵

#8

cxxcomp2010-03-13 22:14

程序代码：

#include<iostream>
using namespace std;

template<typename T>
double showarray(T* array, int n);

template<typename T>
double showarray(T** array, int n);

struct debts
{
    char name[50];
    double amount;
};

int main(void)
{
    int things[6]={13,31,103,301,310,130};

    struct debts mr_e[3]=
    {
        {
            "I am A",
            240.0
        },
        {
            "I am B",
            120.0
        },
        {
            "I am C",
            150.0
        }
    };

    double* pd[3];

    for(int i = 0; i < 3; i++)
        pd[i] = &mr_e[i].amount;

    cout<<"listing mr_e's counts of things: \n" << showarray(things,6) << endl;
    cout<<"listing mr_e's debts: \n" << showarray(pd,3) << endl;

    return 0;
}

template<typename T>
double showarray(T* array,int n)
{
    double sum = 0;
    cout<<"template A\n";
    for(int i = 0; i < n; i++)
        sum += array[i];
    cout << "sum=" << sum << endl;

    return sum;
}

template<typename T>
double showarray(T **array,int n)
{
    double sum = 0;
    cout<<"template A\n";
    for(int i = 0; i < n; i++)
        sum += *array[i];
    cout<< "sum=" << sum << endl;

    return sum;
}

第二个showarray计算结果510.难道不对么？

#9

chengwen10162010-03-13 22:44

从运行结果可以知道，其实程序根本就没有调用B模板函数所以结果会错了  其实改一下用一个函数就可以了

#include<iostream>
using namespace std;

template<class any>
showarray(any array[],int n);

struct debts
{
    char name[50];
    double amount;
};

int main(void)
{
    int things[6]={13,31,103,301,310,130};
    struct debts mr_e[3]=
    {
        {"I am A",240.0},
        {"I am B",120.0},
        {"I am C",150.0}
    };
    double pd[3];

    for(int i=0;i<3;i++)
    pd[i]=mr_e[i].amount;

    cout<<"listing mr_e's counts of things: \n";
    showarray(things,6);
    cout<<"listing mr_e's debts: \n";
    showarray(pd,3);
    return 0;
}

template<class any>
showarray(any array[],int n)
{
    float sum = 0;
    cout<<"template A\n";
    for(int i=0;i<n;i++)
        sum+=array[i];
    cout<<"sum="<<sum;
    cout<<endl;
    return sum;
}