Essential C++ 3.1 节的代码练习——哨兵方式

2020-12-08 13:30

阅读:598

标签:==   The   code   col   tor   ret   无法   friend   否则   

#include "IncrementArray.hpp"

template  
element *find_address(element *array, int size, element &value)
{
    if (! array || size 1)
    {
        return 0;
    }
    for (int i = 0; i array)
    {
        if ((*array) == value)
        {
            return array;
        }
    }
    return 0;
}

template  
element *use_sentinel(element *first_address, element *sentinel, element &value)
{
    if (! first_address || ! sentinel)
    {
        return 0;
    }
    for (; first_address != sentinel; ++first_address)
    {
        if ((*first_address) == value)
        {
            return first_address;
        }
    }
    return 0;
}

int main()
{
    cout "Hello, Hal.\n";
    string string_array[9] = {"hey", "hey", "you", "you", "I", "Don‘t", "Like", "Your", "Girlfriend"};

    vectorstring> avril(string_array, string_array + 9);
    string who = "Girlfriend";

    cout "I don‘t like your Girlfriend. I know her address: " 0]), 9, who)  endl;


    int integer_array[4] = {1, 2, 3, 4};
    int four = 4;
    cout "Where‘s 4? Oh, here it is: " 0]), &(integer_array[0]) + 5, four)  endl;

    int ia[8] = { 1, 1, 2, 3, 5, 8, 13, 21};
    double da[8] = {1.0,2.0,3.0,4.0,5.0,6.0,7.0,8.0};
    string sa[4] = {"lim","aaa","ddd","dcc"};

    int *pi = use_sentinel(ia,ia+8,ia[3]);
    double *pd = use_sentinel(da,da+8,da[3]);
    string *ps = use_sentinel(sa, sa+4, sa[2]);

    cout "ps=" " pd=" " pi="  endl;

    return 0;
}

输出:

Hello, Hal.
I don‘t like your Girlfriend. I know her address: 0x1b1b70
Where‘s 4? Oh, here it is: 0x72fc6c
ps=0x72fbb0 pd=0x72fc08 pi=0x72fc3c
 
添加另一个函数:
template const elemType * find_ver5(const elemType *first,
            const elemType *last, const elemType &value )
{
    if ( ! first || ! last )
        return 0;

    // while first does not equal last,
    // compare value with element addressed by first
    // if the two are equal, return first
    // otherwise, increment first to address next element

    for ( ; first != last; ++first )
        if ( *first == value )
            return first;

    return 0;
}
main函数中需要这么定义,加const。
const
int *pi = find_ver5(ia,ia+8,ia[3]);
否则无法编译通过。

Essential C++ 3.1 节的代码练习——哨兵方式

标签:==   The   code   col   tor   ret   无法   friend   否则   

原文地址:https://www.cnblogs.com/CodeWorkerLiMing/p/10992038.html


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