预处理
先去引入include(包含)
include 引入某个文件
include<iostream>
引入iostream
iostream 输入输出流
cout 输出
系统内置用尖括号
自己创建用引号要加.h
using使用
nemespace命名空间
可以用std的count end cin
using std::cout;
using std::end;
using std::cin;
预处理
先去引入include(包含)
include 引入某个文件
include<iostream>
引入iostream
iostream 输入输出流
cout 输出
系统内置用尖括号
自己创建用引号要加.h
using使用
nemespace命名空间
可以用std的count end cin
using std::cout;
using std::end;
using std::cin;
宏可以代表任意字符串
定义宏后不可以有分号
类型起别名
默认情况下cin是通过指定特殊字符来判断是否输入结束的
按字符串大小输入字符串
cin,getline(字符串变量名,字符串大小)
例子:
cin.getline(name, 20);
c++申请堆内存
int *p = NULL;
if(NULL == p)
{
// 申请内存空间
p = new int;
}
*p = 20;
cout << *p << endl;
释放内存空间
delete p;
c申请堆内存
int *p = NULL;
if(NULL == p)
{
p = (int*)malloc(sizeof(int));
}
*p = 20;
printf("*p = %d\n", *p);
free(p);
int *arr = NULL;
arr = new int[20];
arr[0] = 90;
*(arr + 1) = 80;
delete[] p;
数组
array<int, 20> a1 = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 0 };
array<int, 20> a2 = { 0 };
a2 = a1;
#include <iostream>
#include <string>
#include <array>
using namespace std;
// 创建数组actior, 30个char
// 创建数组chuck,13个float
void CreationArray(void);
// 创建一个结构体糖块CandyBar,包含三个成员,品牌,重量(浮点型),卡路里(整形)
// 声明结构体创建变量名为snack, 初始化值为Mocha Munch, 2.3, 500,最后显示变量
typedef struct CandyBar {
string brank;
double weight;
int calorie;
}sweets;
sweets CandyBarFunc(sweets snackNumber);
// typedef sweets *(candy)(sweets snackNumber);
// 编写一个程序,用户输入三次50的成绩,显示次数和平均成绩。使用array对象来存储数据
void GradeFunc(int* num, double* ave);
int main(void)
{
// char website[] = "sikiedu";
// cout << website << endl;
// c++
//int* p = NULL;
//if (NULL == p)
//{
// p = new int;
//}
//*p = 20;
//delete p;
//// c
//int* p1 = NULL;
//if (NULL == p1)
//{
// p1 = (int*)malloc(sizeof(int));
//}
//*p1 = 20;
//free(p1);
// c++11中新的数组创建方式:数组的模板类创建
//array<int, 20> a1 = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 0 };
//array<int, 20> a2 = { 0 };
//a2 = a1;
// 第二题
sweets snack;
snack.brank = "0";
snack.weight = 0.0;
snack.calorie = 0;
snack = CandyBarFunc(snack);
cout << "糖块的品牌:" << snack.brank << ",糖块的重量为:" << snack.weight << ",糖块的卡路里为:" << snack.calorie << "." << endl;
// 第三题
int num = 0;
double ave = 0;
GradeFunc(&num, &ave);
cout << "次数:" << num << ",平均成绩:" << ave << endl;
return 0;
}
void CreationArray(void)
{
char actior[30];
float chuck[13];
array<char, 30> actior1;
array<float, 13> chuck1;
char* actior2 = new char[30];
float* chuck2 = new float[13];
delete[] actior2;
delete[] chuck2;
char* actior3 = (char*)malloc(sizeof(char) * 30);
float* chuck3 = (float*)malloc(sizeof(float) * 13);
free(actior3);
free(chuck3);
}
sweets CandyBarFunc(sweets snackNumber)
{
snackNumber.brank = "Mocha Munch";
snackNumber.weight = 2.3;
snackNumber.calorie = 500;
return snackNumber;
}
void GradeFunc(int* num, double* ave)
{
const int temp = 3;
array<int, temp> number;
cout << "输入三次成绩:" << endl;
cout << "第一次:";
cin >> number[0];
cout << "第二次:";
cin >> number[1];
cout << "第三次:";
cin >> number[2];
*num = temp;
*ave = (number[0] + number[1] + number[2]) / temp;
}
int girlsNumber;
int boysNumber;
int total;
cout << "请输入女生数量:";
cin >> girlsNumber;
cout << "请输入男生数量:";
cin >> boysNumber;
total = girlsNumber + boysNumber;
int percent = (girlsNumber / float(total)) * 100;//把这个小数乘以100就是百分比 这里total使用了强制类型转换
cout << percent << "%" << endl;
全选注释:// /**/
ctrl+k 再 ctrl+c
ctrl+k 再 ctrl+u
划重点
新式for循环的用法和改变数组值的用法
using std::cout;
using std::endl;
using std::cin;
ctrl+k,c
ctrl+k,u
using namespace std;
//using std::cout;
//using std::endl;
//using std::cin;
int age;
cout << "兄弟,贵庚呀" << endl;
scanf_s("%d", &age);//c
printf("--C--%d\n",age);
printf("兄弟你包含了%d个月啊\n", age * 12);
cin >> age;//c++
cout << "--c++--" << age << endl;
cout << "兄弟你包含了" << age * 12 << "个月哟" << endl;
cin.get();
return 0;
1. float height;
cout << "哥们,你多高耶?" << endl;
cin >> height;
if (height <= 3)
{
cout << (height * 100) << "cm" << endl;
}
else
{
cout << height << endl;
}
2. double lSeconds;
cout << "哥们,输入随便一个以秒为单位的数字,哥哥我分分钟给你算出来是多少天多少小时多少分钟?不信你输个试试" << endl;
cin >> lSeconds;
cout << "来了" << endl;
cout << lSeconds / 60 << " " << "分钟" << endl;
cout << lSeconds / 3600 << " " << "小时" << endl;
cout << lSeconds / (3600 * 24) << " " << "天" << endl;
3. cout << "兄弟,你们班上有几个男的耶?" << endl;
float Male;
cin >> Male;
cout << "几个女的咧?" << endl;
float Female;
cin >> Female;
cout << "我靠,你们班的女生占比百分之" << short((Female / (Male + Female)) * 100) << ",你们有福了" << endl;
注释快捷键ctrl+K ctrl+C
取消注释快捷键ctrl+K ctrl+U
long iSeconds;
cout << "来个以秒为单位的数字" << endl;
cin >> iSeconds;
int days = iSeconds / (24 * 60 * 60);
int hours = (iSeconds % (24 * 60 * 60)) / (60 * 60);
int minutes = (iSeconds % (60 * 60)) / 60;
int seconds = iSeconds % 60;
printf("来了,%d天%d小时%d分钟%d秒\n", days, hours, minutes, seconds);
cout << days * 24 * 60 * 60 + hours * 60 * 60 + minutes * 60 + seconds;
cout << "请输入数字,结束请输入0" << endl;
float a ;
cin >> a;
float total = 0;
for (; a != 0;) {
total += a;
cout <<"当前结果"<< total << endl;
cout << "请输入数字,结束请输入0" << endl;
cin >> a;
} //不用判断语句也是完成该题目的。。。
1.
char actor1[30] = {};
char* pActor = new char[30];
delete[] pActor;
array<char, 30> actor2 = {'a','b','c' };
array<char, 30> actor3 = { 'A','B','C','D','E' };
char* pc2 = &actor2[0];
char* pc3 = &actor3[0];
cout << pc2 << "," << pc3 << endl;
string name = "Haleeco";
char* pc = &name[0];
cout << pc << endl;
string* ps = &name;
cout << ps << endl;
float chuck1[13] = {};
float* pChuck = new float[13];
delete[] pChuck;
array<float, 13> chuck2 = {0.1f,0.2f,0.3f};
array<float, 13> chuck3 = {0.3f,0.2f,0.1f,0.f};
chuck3 = chuck2;
float* pf1 = &chuck2[0];
float* pf2 = &chuck3[0];
float* pf = chuck1;
cout << pf1 << "," << pf2 << "," << pf << endl;
2.
struct CandyBar
{
string brand;
float weight;
int calorie;
};
int main()
{
CandyBar snack{ "Mocha Munch",2.3,500 };
cout << snack.brand << "-" << snack.weight << "-" << snack.calorie << endl;
}
3.
struct Score
{
int NumberOfTimes;
float Archiemement;
};
int main()
{
array<Score, 3> archi;
archi[0].NumberOfTimes = 1;
cout << archi[0].NumberOfTimes << ":";
cin >> archi[0].Archiemement;
archi[1].NumberOfTimes = 2;
cout << archi[1].NumberOfTimes << ":";
cin >> archi[1].Archiemement;
archi[2].NumberOfTimes = 3;
cout << archi[2].NumberOfTimes << ":";
cin >> archi[2].Archiemement;
float AverageScore = (archi[0].Archiemement + archi[1].Archiemement + archi[2].Archiemement) / 3;
cout << AverageScore << endl;
}
1. 01234\n
2. 0369\n
12\n
3. 6\n8
4. k = 8\n
5.
int i = 0, j = 1;
for (; i < 7; i++)
{
cout << j << " ";
j *= 2;
}
cout << endl;
6. int a, b;
cout << "please enter two int.one:";
cin >> a;
cout << "please enter two int.two:";
cin >> b;
if (a > b)
{
for (int i = b; i <= a; i++)
{
for (int j = a; j >= b; j--)
{
cout << i + j << ",";
}
}
}
else
{
for (int i = b; i >= a; i--)
{
for (int j = a; j <= b; j++)
{
cout << i + j << ",";
}
}
}
7. int a = 0, sum = 0;
do
{
cout << "Plase enter a int:";
cin >> a;
sum += a;
cout << sum << endl;
} while (a != 0);