C.Primer.Plus(第六版)第八章 编程练习

#include<iostream>#include<string>using namespace std;int pro_8_1_number=0;void show_str(const char* name,int i=0);struct CandyBar{    char* name;    float weight;    int calories;};struct stringy{    char* str;    int ct;};void set_candybar(CandyBar &candybar,char* ps_char="Millennum Munch",double weight=2.85,int calories=350);void show_candybar(const CandyBar &candybar);void show_pro_8_3(string &jerr_str);void show_8_4(const stringy str1,int x=0);void show_8_4(const char str2[],int x=0);char* set_8_4(stringy &str3 ,char test[]);template <typename T>//8.5T Max(T arr[]){    int key_max=arr[0];    for(int i=1;i<5;i++)    {        if(arr[i]>key_max)            key_max=arr[i];    }    return key_max;}   template <typename T>//8.6T maxn(T array[],int num){    int key_max=array[0];    for(int i=0;i<num;i++)    {        if(array[i]>key_max)            key_max=array[i];    }    return key_max;}template<> char* maxn<char*>(char* arr[],int number)//具体化{       int max=0;    for(int i=1;i<number;i++)    {        if(strlen(arr[i])>strlen(arr[0]))               max=i;    }    return arr[max];}struct debts{    char name[10];    double amount;};template <typename T>T ShowArray_8_7(T *arr,int n){    int sum=0;    for(int i=0;i<n;i++)        sum+=arr[i];    return sum;}template <typename T>T ShowArray_8_7(T* *arr,int n)//在vc6.0中该定义存在二义性，函数参数可解释为(T*)*/(T)**,其中括号表示返回值类型，前者与上一个函数等价，后者调用含指针参数的函数，vc6.0不会进行最优选择而是报错提示。{    double sum=0;    for(int i=0;i<n;i++)        sum+=(*arr[i]);    return sum;}int main(){/*  //8.1    const char arr[20]="jerry peng";    show_str(arr);    cout<<endl;    show_str(arr,1);*//*  //8.2    CandyBar jerr_box;    set_candybar(jerr_box);    show_candybar(jerr_box);    set_candybar(jerr_box,"jerry_peng",22.2,2);    show_candybar(jerr_box);*//* //8.3    string jerr_str;    show_pro_8_3(jerr_str); */ /*   //8.4    stringy beany;    char testing[]="Reality isnt what is used to be.";    char* ps=set_8_4(beany,testing);//在函数中使用动态分配数组，将指向的地址赋给另一个指针用于释放内存。    show_8_4(beany);    show_8_4(beany,2);    testing[0]='D';    testing[2]='U';    show_8_4(testing);    show_8_4(testing,2);    show_8_4("Dn=one!");    delete [] ps;*//*  //8.5    int arr_8_5[5]={1,233,232,214,4};    double doulbe_8_5[5]={1231,32442,23532,21,35363};    cout<<Max(arr_8_5)<<endl;    cout<<Max(doulbe_8_5)<<endl;*//*  //8.6    int arr_8_6[6]={23,43,234,53,54,5};    double darr_8_6[4]={239,345,22,325};    cout<<maxn(arr_8_6,6)<<endl;    cout<<maxn(darr_8_6,4)<<endl;    char* str_8_6[5]={"sdfsfs sdfs","sdfgdxf dfjsdkd","i miss you","what happened?","are you kidding me?"};    cout<<maxn<char*>(str_8_6,5)<<endl;    cout<<int(maxn<char*>(str_8_6,5))<<endl;*//*  //8.7    int things[6]={1,2,34,5,6,77};    struct debts pro_str[3]=    {        {"xx",2400.0},        {"yy",1200.0},        {"zz",2999.0}    };    double *pd[3];    for(int i=0;i<3;i++)        pd[i]=&pro_str[i].amount;    cout<<ShowArray_8_7(things,6)<<endl;//  ShowArray_8_7(pd,1);   二义性*/    return 0;}/*  //8.1void show_str(const char* name,int i){    pro_8_1_number++;    if(i==0)        cout<<name<<endl;    else    {        for(;pro_8_1_number>0;pro_8_1_number--)            cout<<name<<endl;    }}*//*void set_candybar(CandyBar &candybar,char* ps_char,double weight,int calories){    candybar.calories=calories;    candybar.name=ps_char;    candybar.weight=weight;}void show_candybar(const CandyBar &candybar){    cout<<candybar.calories<<"\t"<<candybar.name<<"\t"<<candybar.weight<<endl;}*//*void show_pro_8_3(string &jerr_str){    cout<<"Please enter a string (q to quit):";    while(getline(cin,jerr_str)&&jerr_str!="q")    {        cin.get();        for(int i=jerr_str.size();i>0;i--)        {            jerr_str[i-1]=toupper(jerr_str[i-1]);        }        cout<<jerr_str;        cout<<"\nPlease enter next string (q to quit):";    }    cout<<"Bye!";}*//*  //8.4void show_8_4(const stringy str1,int x){    for(int j=strlen(str1.str);x<j;x++)        cout<<str1.str[x];    cout<<endl;}void show_8_4(const char str2[],int x){    for(int k=strlen(str2);x<k;x++)        cout<<str2[x];    cout<<endl;}char* set_8_4(stringy &str3 ,char test[]){    str3.str=new char[strlen(test)+1];    strcpy(str3.str,test);    return str3.str;}*/