📢 声明：
1）本文仅供学术交流，非商用。
2）博主才疏学浅，文中如有不当之处，请各位指出，共同进步，谢谢。
3）此属于第一版本，若有错误，还需继续修正与增删。还望大家多多指点。
4）大家都共享一点点，一起为祖国科研的推进添砖加瓦。
👉 学习路线
- 📂 【资源】一个C/C++开发工程师的学习路线（已经无路可退，唯有逆风飞翔）【内附资源页】
- 💻 【GitHub】Cpp-Prime5 + Cpp-Primer-Plus6 源代码和课后题
- 📚 《C++ Primer》学习笔记/习题答案 总目录
〇、✏ 前言
为了更好地记录学过的C++知识，作者在过去的两个月里，将每个知识点对应的小例子总结下来，分享给大家 💖，希望大家喜欢 😁。
下面开始正文，全程英文注释：
一、🚀 你好，世界
牙牙学语的开始。
#include <iostream>
int main()
{
using namespace std;
cout << "Hello,World" << endl;
system("pause");
return 0;
}
二、🍄 数据类型
int、short、long、long long、char、float、double、long double 的位数，最大值，最小值。
#include <iostream>
#include <climits>
int main()
{
using namespace std;
int n_int = INT_MAX; // initialize n_int to max int value
short n_short = SHRT_MAX; // symbols defined in climits file
long n_long = LONG_MAX;
long long n_llong = LLONG_MAX;
char n_char = CHAR_MAX;
float n_float = FLT_MAX;
double n_double = DBL_MAX;
long double n_ldouble = LDBL_MAX;
// sizeof operator yields size of type or of variable
cout << "Sizeof:" << endl;
cout << "int is " << sizeof (int) << " bytes." << endl;
cout << "short is " << sizeof n_short << " bytes." << endl;
cout << "long is " << sizeof n_long << " bytes." << endl;
cout << "long long is " << sizeof n_llong << " bytes." << endl;
cout << "char is " << sizeof n_char << " bytes." << endl;
cout << "float is " << sizeof n_float << " bytes." << endl;
cout << "double is " << sizeof n_double << " bytes." << endl;
cout << "long double is " << sizeof n_ldouble << " bytes." << endl;
cout << endl;
cout << "Maximum values:" << endl;
cout << "int: " << n_int << endl;
cout << "short: " << n_short << endl;
cout << "long: " << n_long << endl;
cout << "long long: " << n_llong << endl;
cout << "char is " << n_char << endl;
cout << "float is " << n_float << endl;
cout << "double is " << n_double << endl;
cout << "long double is " << n_ldouble << endl;
cout << endl;
cout << "Minimum values:" << endl;
cout << "int: " << INT_MIN << endl;
cout << "short: " << SHRT_MIN << endl;
cout << "long: " << LONG_MIN << endl;
cout << "long long: " << LLONG_MIN << endl;
cout << "char is " << CHAR_MIN << endl;
cout << "float is " << FLT_MIN << endl;
cout << "double is " << DBL_MIN << endl;
cout << "long double is " << LDBL_MIN << endl;
cout << endl;
cout << "Bits per byte = " << CHAR_BIT << endl;
system("pause");
return 0;
}
三、🍅 算术运算符
加法、减法、乘法、除法、求模。
#include <iostream>
int main()
{
using namespace std;
int hats, heads;
cout << "Enter a number: ";
cin >> hats;
cout << "Enter another number: ";
cin >> heads;
cout << "hats = " << hats << "; heads = " << heads << endl;
cout << "hats + heads = " << hats + heads << endl;
cout << "hats - heads = " << hats - heads << endl;
cout << "hats * heads = " << hats * heads << endl;
cout << "hats / heads = " << hats / heads << endl;
cout << "hats % heads = " << hats % heads << endl;
system("pause");
return 0;
}
四、🍆 复合类型
4.1、🍉 一维数组、字符串、string
#include <iostream>
#include <cstring>
#include <string> // make string class available
const int Size = 15;
int main()
{
using namespace std;
int yams[3]; // creates array with three elements
yams[0] = 7; // assign value to first element
yams[1] = 8;
yams[2] = 6;
cout << "Total yams = ";
cout << yams[0] + yams[1] + yams[2] << "." << endl;
cout << "The second yams = ";
cout << yams[1] << ".";
cout << "\nSize of yams array = " << sizeof yams;
cout << " bytes.\n";
cout << endl;
cout << "********************************分割线********************************" << endl;
cout << endl;
char name[Size] = "C++owboy"; // initialized array
cout << "Well, " << name << ", your name ";
cout << "is stored in an array of " << sizeof(name) << " bytes.\n";
cout << "Your initial is " << name[0] << ".\n";
name[3] = '\0'; // set to null character
cout << "Here are the first 3 "
"characters of my name: ";
cout << name << "." << endl;
cout << endl;
cout << "********************************分割线********************************" << endl;
cout << endl;
string s1 = "penguin";
string s2, s3;
s2 = "buzzard";
cout << "You can assign two string object: "
"s1 is " << s1 << ", "
"s2 is " << s2 << endl;
s3 = s1 + s2;
cout << "You can concatenate strings: s3 = s1 + s2";
cout << " = " << s3;
cout << "\nSize of s3 = " << sizeof s3 << " bytes.\n" << endl;
system("pause");
return 0;
}
4.2、🍊 结构、共用体、枚举
#include <iostream>
struct inflatable // structure declaration
{
char name[20];
float volume;
double price;
};
union one4all{
int int_val;
long long_val;
double double_val;
};
enum spectrum{
red, orange, yellow, green
};
int main()
{
using namespace std;
inflatable guests[2] = // initializing an array of structs
{
{ "Bambi", 0.5, 21.99 },// first structure in array
{ "Godzilla", 2000, 565.99 } // next structure in array
};
cout << "The guests " << guests[0].name << " and " << guests[1].name
<< "\nhave a combined volume of "
<< guests[0].volume + guests[1].volume << " cubic feet.\n";
inflatable guest =
{
"Glorious Gloria", // name value
1.88, // volume value
29.99 // price value
}; // guest is a structure variable of type inflatable
// It's initialized to the indicated values
inflatable pal =
{
"Audacious Arthur",
3.12,
32.99
}; // pal is a second variable of type inflatable
// NOTE: some implementations require using static inflatable guest
cout << "Expand your guest list with " << guest.name;
cout << " and " << pal.name << "!\n";
cout << "You can have both for $";
cout << guest.price + pal.price << "!\n";
inflatable choice;
choice = guest; // assign one structure to another
cout << "The choice: " << choice.name << " for $";
cout << choice.price << endl;
cout << endl;
cout << "********************************分割线********************************" << endl;
cout << endl;
one4all pail;
pail.int_val = 15;
cout << "The int_val of pail is " << pail.int_val << endl;
cout << "The double_val of pail is " << sizeof(pail.double_val) << " bytes.\n";
cout << endl;
cout << "********************************分割线********************************" << endl;
cout << endl;
spectrum band;
band = green;
cout << "The band green is " << band << endl;
int color = orange;
color = 1 + red;
band = spectrum(color);
cout << "The color of 'color = 1 + red' is " << band << endl;
system("pause");
return 0;
}
4.3、🍕 二维数组、字符串、string
#include <iostream>
#include <string>
#include <array>
const int Cities = 5;
const int Years = 4;
int main()
{
using namespace std;
const string cities[Cities] = // array of pointers
{ // to 5 strings
"Gribble City",
"Gribbletown",
"New Gribble",
"San Gribble",
"Gribble Vista"
};
array<array<int, Cities>, Years> maxtemps =
/* int maxtemps[Years][Cities] = // 2-D array */
{
96, 100, 87, 101, 105, // values for maxtemps[0]
96, 98, 91, 107, 104, // values for maxtemps[1]
97, 101, 93, 108, 107, // values for maxtemps[2]
98, 103, 95, 109, 108 // values for maxtemps[3]
};
cout << "Maximum temperatures for 2008 - 2011\n\n";
for (int city = 0; city < Cities; ++city)
{
cout << cities[city] << ":\t";
for (int year = 0; year < Years; ++year)
cout << maxtemps[year][city] << "\t";
cout << endl;
}
system("pause");
return 0;
}
五、🍇 指针
#include <iostream>
#include <cstring>
struct inflatable // structure definition
{
char name[20];
float volume;
double price;
};
int main()
{
using namespace std;
double * p3 = new double[3]; // space for 3 doubles
p3[0] = 0.2; // treat p3 like an array name
p3[1] = 0.5;
p3[2] = 0.8;
cout << "p3[1] is " << p3[1] << ".\n";
p3 = p3 + 1; // increment the pointer
cout << "Now p3[1] is " << p3[1] << ".\n";
p3 = p3 - 1; // point back to beginning
delete[] p3; // free the memory
cout << endl;
cout << "********************************分割线********************************" << endl;
cout << endl;
char animal[20] = "bear"; // animal holds bear
char * ps; // uninitialized
cout << animal << " and "; // display bear
ps = animal; // set ps to point to string
cout << ps << "!\n"; // ok, same as using animal
cout << "Before using strcpy():\n";
cout << animal << " at " << (int *)animal << endl;
cout << ps << " at " << (int *)ps << endl;
ps = new char[strlen(animal) + 1]; // get new storage
strcpy(ps, animal); // copy string to new storage
cout << "After using strcpy():\n";
cout << animal << " at " << (int *)animal << endl;
cout << ps << " at " << (int *)ps << endl;
delete[] ps;
cout << endl;
cout << "********************************分割线********************************" << endl;
cout << endl;
inflatable * psa = new inflatable; // allot memory for structure
cout << "Enter name of inflatable item: ";
cin.get(psa->name, 20); // method 1 for member access
cout << "Enter volume in cubic feet: ";
cin >> (*psa).volume; // method 2 for member access
cout << "Enter price: $";
cin >> psa->price;
cout << "Name: " << (*psa).name << endl; // method 2
cout << "Volume: " << psa->volume << " cubic feet\n"; // method 1
cout << "Price: $" << psa->price << endl; // method 1
delete psa; // free memory used by structure
system("pause");
return 0;
}
六、🍈 模板类
vector、array。
#include <iostream>
#include <vector> // STL C++98
#include <array> // C++0x
int main()
{
using namespace std;
// C, original C++
double a1[4] = { 1.2, 2.4, 3.6, 4.8 };
// C++98 STL
vector<double> a2(4); // create vector with 4 elements
// no simple way to initialize in C98
a2[0] = 1.0 / 3.0;
a2[1] = 1.0 / 5.0;
a2[2] = 1.0 / 7.0;
a2[3] = 1.0 / 9.0;
// C++0x -- create and initialize array object
array<double, 4> a3 = { 3.14, 2.72, 1.62, 1.41 };
array<double, 4> a4;
a4 = a3; // valid for array objects of same size
// use array notation
cout << "a1[2]: " << a1[2] << " at " << &a1[2] << endl;
cout << "a2[2]: " << a2[2] << " at " << &a2[2] << endl;
cout << "a3[2]: " << a3[2] << " at " << &a3[2] << endl;
cout << "a4[2]: " << a4[2] << " at " << &a4[2] << endl;
// misdeed
a1[-2] = 20.2;
cout << "a1[-2]: " << a1[-2] << " at " << &a1[-2] << endl;
cout << "a3[2]: " << a3[2] << " at " << &a3[2] << endl;
cout << "a4[2]: " << a4[2] << " at " << &a4[2] << endl;
system("pause");
return 0;
}
七、🍌 循环
7.1、🍒 for循环
#include <iostream>
const int ArSize = 15; // example of external declaration
int main()
{
using namespace std;
int i; // create a counter
// initialize; test ; update
cout << "Counting by positive(++)" << ".\n";
for (i = 0; i < 5; i++)
cout << "C++ knows loops.\n";
cout << "Counting by negative(--)" << ".\n";
for (i = 5; i > 0; i--)
cout << "C++ knows loops.\n";
int by = 3;
cout << "Counting by " << by << "s:\n";
for (i = 5; i > 0; i-=by)
cout << "C++ knows loops.\n";
cout << "C++ knows when to stop.\n";
cout << endl;
cout << "********************************分割线********************************" << endl;
cout << endl;
long long factorials[ArSize];
factorials[1] = factorials[0] = 1LL;
for (int i = 2; i < ArSize; i++)
factorials[i] = i * factorials[i - 1];
for (int i = 0; i < ArSize; i++)
cout << i << "! = " << factorials[i] << endl;
cout << endl;
cout << "********************************分割线********************************" << endl;
cout << endl;
int a = 20;
int b = 20;
cout << "a = " << a << ": b = " << b << "\n";
cout << "a++ = " << a++ << ": ++b = " << ++b << "\n";
cout << "a = " << a << ": b = " << b << "\n";
system("pause");
return 0;
}
7.2、🍓 while循环
#include <iostream>
#include <ctime> // describes clock() function, clock_t type
const int ArSize = 20;
int main()
{
using namespace std;
cout << "Count the delay time, in seconds.";
cout << "starting\a\n";
clock_t start = clock();
char name[ArSize] = "Fred";
cout << "Your first name, please is " << name << endl;
cout << "Here is your verticalized and ASCIIized name:\n";
int i = 0; // start at beginning of string
while (name[i] != '\0') // process to end of string
{
cout << name[i] << ": " << int(name[i]) << endl;
i++; // don't forget this step
}
cout << "Loop done \a\n";
clock_t end = clock();
double endtime = (double)(end - start) / CLOCKS_PER_SEC;
cout << "Total time is: " << endtime << "s" << endl;
system("pause");
return 0;
}
7.3、🍔 do while循环
#include <iostream>
int main()
{
using namespace std;
int n;
cout << "Enter numbers in the range 1-10 to find ";
cout << "my favorite number\n";
do
{
cin >> n; // execute body
} while (n != 7); // then test
cout << "Yes, 7 is my favorite.\n";
system("pause");
return 0;
}
八、🍍 分支
8.1、🍖 if else语句
#include <iostream>
const int Fave = 27;
int main()
{
using namespace std;
int n;
cout << "Enter a number in the range 1-100 to find ";
cout << "my favorite number: ";
do
{
cin >> n;
if (n < Fave)
cout << "Too low -- guess again: ";
else if (n > Fave)
cout << "Too high -- guess again: ";
else
cout << Fave << " is right!\n";
} while (n != Fave);
system("pause");
return 0;
}
8.2、🍘 switch语句
#include <iostream>
using namespace std;
void showmenu(); // function prototypes
void report();
void comfort();
int main()
{
showmenu();
int choice;
cin >> choice;
while (choice != 5)
{
switch (choice)
{
case 1: cout << "\a\n";
break;
case 2: report();
break;
case 3: cout << "The boss was in all day.\n";
break;
case 4: comfort();
break;
default: cout << "That's not a choice.\n";
}
showmenu();
cin >> choice;
}
cout << "Bye!\n";
system("pause");
return 0;
}
void showmenu()
{
cout << "Please enter 1, 2, 3, 4, or 5:\n"
"1) alarm 2) report\n"
"3) alibi 4) comfort\n"
"5) quit\n";
}
void report()
{
cout << "It's been an excellent week for business.\n"
"Sales are up 120%. Expenses are down 35%.\n";
}
void comfort()
{
cout << "Your employees think you are the finest CEO\n"
"in the industry. The board of directors think\n"
"you are the finest CEO in the industry.\n";
}
8.3、🍚 continue / break语句
#include <iostream>
const int ArSize = 80;
int main()
{
using namespace std;
char line[ArSize];
int spaces = 0;
cout << "Enter a line of text:\n";
cin.get(line, ArSize);
cout << "Complete line:\n" << line << endl;
cout << "Line through first period:\n";
for (int i = 0; line[i] != '\0'; i++)
{
cout << line[i]; // display character
if (line[i] == '.') // quit if it's a period
break;
if (line[i] != ' ') // skip rest of loop
continue;
spaces++;
}
cout << "\n" << spaces << " spaces\n";
cout << "Done.\n";
system("pause");
return 0;
}
九、🍎 简单文件处理
9.1、🍜 文本写入
#include <iostream>
#include <fstream> // for file I/O
int main()
{
using namespace std;
char automobile[50];
int year;
double a_price;
double d_price;
ofstream outFile; // create object for output
outFile.open("carinfo.txt"); // associate with a file
cout << "Enter the make and model of automobile: ";
cin.getline(automobile, 50);
cout << "Enter the model year: ";
cin >> year;
cout << "Enter the original asking price: ";
cin >> a_price;
d_price = 0.913 * a_price;
// display information on file with outFile
// using outFile instead of cout
outFile << fixed;
outFile.precision(2);
outFile.setf(ios_base::showpoint);
outFile << "Make and model: " << automobile << endl;
outFile << "Year: " << year << endl;
outFile << "Was asking $" << a_price << endl;
outFile << "Now asking $" << d_price << endl;
outFile.close(); // done with file
system("pause");
return 0;
}
9.2、🍞 文本读出
#include <iostream>
#include <fstream> // file I/O support
#include <cstdlib> // support for exit()
const int SIZE = 60;
int main()
{
using namespace std;
char filename[SIZE];
ifstream inFile; // object for handling file input
cout << "Enter name of data file: ";
cin.getline(filename, SIZE);
inFile.open(filename); // associate inFile with a file
if (!inFile.is_open()) // failed to open file
{
cout << "Could not open the file " << filename << endl;
cout << "Program terminating.\n";
// cin.get(); // keep window open
exit(EXIT_FAILURE);
}
double value;
double sum = 0.0;
int count = 0; // number of items read
inFile >> value; // get first value
while (inFile.good()) // while input good and not at EOF
{
++count; // one more item read
sum += value; // calculate running total
inFile >> value; // get next value
}
if (inFile.eof())
cout << "End of file reached.\n";
else if (inFile.fail())
cout << "Input terminated by data mismatch.\n";
else
cout << "Input terminated for unknown reason.\n";
if (count == 0)
cout << "No data processed.\n";
else
{
cout << "Items read: " << count << endl;
cout << "Sum: " << sum << endl;
cout << "Average: " << sum / count << endl;
}
inFile.close(); // finished with the file
system("pause");
return 0;
}
如果想要更多的资源，欢迎关注 @我是管小亮，文字强迫症MAX~
回复【福利】即可获取我为你准备的大礼，包括C++，编程四大件，NLP，深度学习等等的资料。
想看更多文（段）章（子），欢迎关注微信公众号「程序员管小亮」~
参考文章
- 《C++ Primer Plus》第六版
转载：https://blog.csdn.net/TeFuirnever/article/details/103604137
查看评论