#include <iostream>

#include <algorithm>

#include <iterator>

#include <iomanip>

#include <cstring>

using namespace std;

int result(int, int);

void main1();

void main2();

const int k = 2;

struct Point {

int x, y;

};

void main1() {

int z(0), b(50);//调用构造函数，等同于z = 50

Point a;

cout << "输入两个整数（以空格区分）：";

cin >> a.x >> a.y;

z = (a.x + a.y) * k;

z = result(z, b);

cout << "计算结果如下：" << endl;

cout << "((" << a.x << "+" << a.y << ")*" << k << ")+" << b << "=" << z << endl;

}

int result(int a, int b) {

return a + b;

}

void main2() {

double *pDouble = new double[3];

for (int i = 0; i < 3; i++) {

cout << "请输入一个数字" << endl;

cin >> *(pDouble + i);

}

for (int j = 0; j < 3; j++) {

cout << *(pDouble + j) << " ";

}

delete pDouble;

}

void constTest() {

int *p1 = new int(5);

int *&p2 = p1; //是指针的引用

// int * * p3 = &p1;

const int y = 58; //常量，不能改变值

const int *p = &y;//指向常量的指针

// * p = 2;

cout << *p << endl;

cout << p << endl;

cout << &p << endl;

cout << y << endl;

cout << &y << endl;

}

//1.6

bool compare(int a, int b) {

return a > b;

}

void coutArray() {

double a[4] = {1.1, 4.4, 3.3, 2.2}, b[4];

// 数组复制到流中输出 p1:开始位置，p2： 结束位置 p3：输出流

cout << "数组a" << endl;

copy(a, a + 4, ostream_iterator<double>(cout, " "));

cout << endl;

cout << "逆向输出数组a" << endl;

reverse_copy(a, a + 4, ostream_iterator<double>(cout, " "));

cout << endl;

//复制到数组b p1:开始位置，p2： 结束位置 p3，数组开始

copy(a, a + 4, b);

//输出数组b

cout << "数组a" << endl;

copy(b, b + 4, ostream_iterator<double>(cout, " "));

cout << endl;

/* for (int i = 0; i < 4; ++i) {

cout << b[i] << endl;

}*/

//对数组a进行排序

sort(a, a + 4); //默认升序排序

// sort(a,a+4,compare) 降序排序 ,自己实现

// sort(a, a + 4, greater<double>()); // less<数据类型>()//从小到大排序 greater<数据类型>()//从大到小排序

cout << "升序输出a" << endl;

copy(a, a + 4, ostream_iterator<double>(cout, " "));

cout << endl;

cout << "逆向copy数组a到b" << endl;

reverse_copy(a, a + 4, b);

copy(b, b + 4, ostream_iterator<double>(cout, " "));

cout << endl;

double a1[4] = {1.1, 3.3, 2.2, 4.4};

double *x = find(a1, a1 + 4, 4.4);

//x的地址超出a1地址范围就是没有找到

cout << (x == a1 + 3) << endl;

if (x == a1 + 4) {

cout << "没有找到值为4.4的元素" << endl;

} else {

cout << "有值为" << *x << "的数组元素" << endl;

}

delete x;

//double i 每加一，内存地址增加8个字节 double类型8个字节，64位

for (int i = 0; i < 4; ++i) {

cout << "a1+" << i << " = " << a1 + i << " value = " << a1[i] << endl;

}

cout << "x = " << x << " *x = " << *x << endl;

// char char1[] = "ab";

char char2[] = {'a', 'b'};

//todo 两者有区别，前者可直接cout输出值，后者会有乱码，不知道是什么。

//todo 2016-07-17 01:00 ,发现是因为char2[] 没有 \0 不会截止， char1长度为3

cout << char2 << endl;

// cout << sizeof(int) << endl; //sizeof 计算内存中占用字节数

//通过sizeof 可计算数组长度

/* for(int i=0;i< sizeof(char1)/ sizeof(char1[0]);i++){

cout<<char1[i]<<" ";

}*/

/* string str = "str";

str.~string();*/

}

void charCopy() {

char a[11] = "wearehere!", b[11];

cout << " sizeof(a) / sizeof(a[0]) = " << sizeof(a) / sizeof(a[0]) << endl;

cout << "strlen(a) = " << strlen(a) << endl; // strlen() 属于<cstring> 中，strlen 遇到\0 会结束，并且不计算结束符

copy(a, a + 11, b);

cout << b << "sizeof(b) / sizeof(b[0]) = " << sizeof(b) / sizeof(b[0]) << endl;

reverse_copy(a, a + 10, b);

cout << b << endl;

for (int i = 0; i < 11; ++i) {

cout << b[i] << endl;

}

}

//1.10 输出符操控定义

void coutOperFun() {

cout.precision(10);

const double PI = 13.141592;

cout << PI << endl;

cout << setprecision(0) << PI << endl;

}

void exercises1() {

int num;

int &ref = num;

ref = ref + 100;

num = num + 50;

}

void exercises2() {

int x = 58, y = 98;

const int *p = &x;

cout << p << endl;

cout << *p << endl;

// *p=65;

p = &y;

cout << p << endl;

cout << *p << endl;

}

void expercises3() {

int x = 58, y = 98, z = 55;

int *const p = &x;

cout << *p << " " << p << endl;

*p = 56;

cout << *p << " " << p << endl;

// p= &y;// p是常量指针，不能作为左值

cout << z << endl;

z = *p;

cout << z << endl;

}

/**

* 分别用ASCII码形式输出 65 和 66

*/

void expercises4_1() {

int char1 = 55, char2 = 56;

cout << char(char1) << endl;

cout << char(char2) << endl;

}

/**

* 编写一个为int型变量分配100个整型量空间的程序

*/

void expercises4_2() {

int *pint = new int[100];

}

/**

* 接收输入的15个float 值，并计算最小值和这些值的和

*/

void expercises4_3() {

float *pfloat = new float[15];

float sum = 0.0f;

//<limits> 头文件中，获取float 最大值,或者 min =0.0f, 当i=0时，把输入的值赋给min

float min = numeric_limits<float>::max();

cout << "请输入15个Float型数字" << endl;

for (int i = 0; i < 15; ++i) {

cin >> *(pfloat + i);

sum += *(pfloat + i);

if (min > *(pfloat + i)) {

min = *(pfloat + i);

}

}

cout << "15个float 数字中最小的是：" << min << ", 15个数字的和是：" << sum << endl;

// int length = sizeof(pfloat)/ sizeof(pfloat[0]);

}

/**

* 找出数组中4的位置，在将数组a复制给数组b,然后将数组a的内容反转在找出4的位置，

* 最后分别输出数组a和b的内容

*/

void expercises4_4() {

int a[] = {1, 2, 3, 4, 5, 6, 7, 8}, b[8];

int *p = find(a, a + 8, 4);

if (p == a + 8) {

cout << "没有找到值为4的数组元素" << endl;

} else {

cout << "找到了值为" << *p << "的数组元素" << endl;

}

copy(a, a + 8, b);

reverse(a, a + 8);

p = find(a, a + 8, 4);

if (p == a + 8) {

cout << "没有找到值为4的数组元素" << endl;

} else {

cout << "找到了值为" << *p << "的数组元素" << endl;

}

copy(a, a + 8, ostream_iterator<int>(cout)); //ostream_iterator 在 <iterator>

cout<<endl;

copy(b, b + 8, ostream_iterator<int>(cout));

}

int main() {

// int num;//不初始化，值是不确定的， static 时默认值是0

// cout << num << endl;

//constTest();

//1.6

//coutArray();

//1.9

//charCopy();

//1.10

//coutOperFun();

// expercises4_2();

// expercises4_3();

expercises4_4();

return 0;

}