C++Primer Plus习题记录-Chapter8

8-2

#include "pch.h"
#include <iostream>
#include <fstream>
#include <cstdlib>
#include <string>
#include <cctype>
#include <array>
#include <iomanip>

using namespace std;
struct CandyBar
{
    string brand;
    double weight;
    int heat;
};
void info_candy(CandyBar &changed_para, char* str, double m, int n);
void show(CandyBar &candy);//test

int main() {
    CandyBar init_para = {
        "Millennium Munch",
        2.85,
        350
    };
    show(init_para);
    char ch[20];
    cin.getline(ch,20);
    double m;
    cin >> m;
    int n;
    cin >> n;
    info_candy(init_para, ch, m, n);
    show(init_para);
    return 0;
}
void info_candy(CandyBar &changed_para, char* str, double m, int n) {
    changed_para.brand = str;
    changed_para.weight = m;
    changed_para.heat = n;
}
void show(CandyBar &candy) {
    cout << candy.brand << "
" << candy.weight << "
" << candy.heat << endl;
}

 8-3

#include "pch.h"
#include <iostream>
#include <fstream>
#include <cstdlib>
#include <string>
#include <cctype>
#include <array>
#include <iomanip>
#include <algorithm>
using namespace std;
void upper(string& lower);
int main() {
    string lower;
    getline(cin, lower);
    while (lower!="q")
    {
        upper(lower);
        cout << lower << endl;
        getline(cin, lower);
    }
    return 0;
}
void upper(string & lower) {
    char *pt= &lower[0];
    int length = lower.size();
    pt[0]=toupper(pt[0]);
    for (int i = 1; i < length; i++) {
        pt[i]=toupper(pt[i]);
    }
}

 8-4

using namespace std;
struct stringy
{
    char* str;
    int ct;
};
void set(stringy &beany, char []);
void show(stringy str,int n=1);
void show(const char* str, int n=1);
int main() {
    stringy beany;
    char testing[] = "Reality isn't what it used to be.";
    set(beany, testing);
    show(beany);
    testing[0] = 'D';
    testing[1] = 'u';
    show(testing);
    show(testing, 3);
    show("Done!");

    return 0;
}
void set(stringy &beany, char ch[]) {
        beany.str = ch;
}
void show(stringy str,int n) {
    for (int i = 0; i < n; i++)
        cout << str.str << endl;
}
void show(const char* str, int n) {
    for (int i = 0; i < n; i++)
        cout << str << endl;
}

 8-5

template<class T>
T maxn(T a[]);

int main() {
    
    int a[5] = { 1,2,3,4,5 };
    double aa[5] = { 2.1,3.1,4.1,1.1,1.0 };
    int max1 = maxn(a);
    double max2 = maxn(aa);
    cout << max1 << ' ' << max2;
    return 0;
}
template<class T>
T maxn(T a[]) {
    T temp=a[0];
    for (int i = 1; i < 5; i++) {
        if (a[i] > temp)
            temp = a[i];
    }
    return temp;
}

 8-6

using namespace std;
template<typename T>
T maxn(T ar[], int n);
template <> const char* maxn(const char* ch[], int n);
int main(void) {
    const char *ch[3] = { "aa","b","ccc" };
    int a[6] = { 1,2,3,4,2,4 };
    double b[4] = { 1.1,2.2,0.3,2.4 };
    int maxa = maxn(a,6);
    double maxb = maxn(b, 4);
    const char* pr;
    pr = maxn(ch, 3);
    cout << maxa << " " << maxb << " " << &pr << " " << static_cast<const void*>(pr);
    return 0;
}
template<typename T>
T maxn(T ar[], int n) {
    T temp;
    temp = ar[0];
    for (int i = 1; i < n; i++) {
        if (ar[i] > temp)
            temp = ar[i];
    }
    return temp;
}
template <> const char* maxn(const char* ch[], int n) {
    const char *temp = ch[0];
    for (int i = 1; i < n; i++) {
        if (strlen(temp) < strlen(ch[i]))
            temp = ch[i];
    }
    return temp;
}

8-7

using namespace std;

template<typename T>
T sumArray(T ar[], int n);
template<typename T>
T sumArray(T* ar[], int n);
struct debts
{
    char name[50];
    double amount;
};
int main(void) {
    int things[6] = { 13,31,103,301,310,130 };
    debts mr[3]= {
        {"Light",13.4},
        {"Lighr",13.1},
        {"Lighy",13.2}
    };
    double* pd[3];
    for (int i = 0; i < 3; i++) {
        pd[i] = &mr[i].amount;
    }
    int sum1;
    sum1=sumArray(things, 6);
    double sum2;
    sum2 = sumArray(pd, 3);
    cout << sum1 << " " << sum2;
    return 0;
}

template<typename T>
T sumArray(T ar[], int n) {
    T sum = 0;
    for (int i = 0; i < n; i++)
        sum += ar[i];
    return sum;
}
template<typename T>
T sumArray(T* ar[], int n) {
    T sum = 0;
    for (int i = 0; i < n; i++)
        sum += *ar[i];
    return sum;
}