C++高手编程笔记.docx

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1、C+简单程序典型案例【案例2-1设计个编写仅包含C+程序基本构成元素的程序 /注释行开始This is the first C+ program.Designed by zrf*/注释行结束#include 包含头文件 using namespace std;打开命名空间 std/ This is the main function 单行注释语句 int main (void)主函数,程序入口块作用域开始int agei声明一个变量age=20J 赋值语句 cout“The age is:n”;输出个字符串coutageendl;输出变量中的值return 0;主函数返回)块作用域结束【案例2

2、-2】计算圆的周长和面积C+语言中常量、变量 #include using namespace std; int main() const float PI=3. 1415926; /float 型常量float厂2.0; 用float型常量初始化变量 coutr=rendl; /输出圆的半径 float length; /float 型变量声明 length=2*Pl*r; 计算圆的周长 coutLength=lengthendl; 输出圆的周长 float area=PI*r*r; 计算圆的面积 coutArea=areaendl; 输出圆的面积 return 0;【案例2-3】整数的简单

3、运算除法、求余运算法和增量减量运算符#include using namespace std;int mainO int x, y;x = 10; y = 3;cout x / y is x / y整数的除法操作 with x % y is x % y endl;整数的取余操作x +; -y ;使用增量减量运算符cout X / y is x / y 、n整数的除法操作 x % y is x % yendl: 整数的取余操作 return 0;【案例2T】多重计数器前置和后置自增运算符#includeusing namespace std;int main () int iCount=l; i

4、Count=(iCount+) + (iCount+) + (iCount+): 后置+ cout“The first iCount=iCountendl;iCount=l; iCount= (+iCount) + (+iCount) + (+iCount); 前置+ coutThe second iCount=iCountendl;iCount=l; iCount=-iCount+:后置+coutThe third iCount二iCountendl;iCount=l; iCount=+iCount;前置+cout“The fourth iCount=iCountendl;return 0;

5、【案例2-5】对整数“10”和“ 20”进行位运算位运算的应用#include using namespace std;intmain()cout”20&10=(20&10)endl;/按位与运算cout*20*10=*(20*10)endl;/按位异或运算cout*20|10=*(20|10)endl;/按位或运算cout20 C20) endl;按位取反运算cout*203=*(203)endl;左移位运算cout-203,(-203) endl;左移位运算cout*203=*(203)endl;右移位运算cout *-203= (-203) endl; 右移位运算 return 0;【案

6、例2-6】实现逻辑“异或”运算逻辑运算应用#include using namespace std;int main () bool p, q;p = true; q 二 true;cout p XOR q is ( (p | | q) & ! (p & q) ) n; 输出异或结果 p = false; q = true;cout p XOR q is ( (p | | q) & ! (p & q) ) n; 输出异或结果 p = true; q = false;cout p XOR q is ( (p I | q) & ! (p & q) ) n; 输出异或结果 p = false; q

7、= false;cout p XOR q is ( (p | | Q)& !(P & q) ) n; 输出异或结果 return 0;【案例2-7】高效筛选器用条件运算符“？ ”构建条件表达式#includeusing namespace std;int main () int iNuml=l, iNum2, iMax;cout“Please input two integers:n*;ciniNumliNum2;iMax = iNumliNum2 ? iNuml : iNum2; 使用条件运算符构建条件表达式 coutThe max integer is: iMaxendl;return 0

8、;) 【案例2-81“多计算与单提取”功能的实现逗号表达式#includeusing namespace std;int main() int Vail, Val2, Val3, Left, Midd, Righ;Left = 10; Midd = 20; Righ = 30;Vali = (Left+, Midd, Righ+); 使用逗号表达式Val2 = (Righ+, Left+, -Midd); 使用逗号表达式Val3 = ( Midd, Righ+, Left+); 使用逗号表达式cout Vail二、tVail nVal2=t*Val2 nVal3=tVal3endl; retu

9、rn 0;【案例2-9】高效的算术运算符复合赋值运算符include using namespace std;int main () int n=20; cout n = n endl;n +=8;coutAftern+=8,n=nendl;使用复合的赋值运算符+二n -=6;coutAftern-=6,n=nendl;使用复合的赋值运算符一二n *=1;cout”Aftern*=1,n=nendl;使用复合的赋值运算符二n /=4;coutAftern/=4,n二nendl;使用复合的赋值运算符/二n %= 3; cout After n %= 3, n 二 n endl; 使用复合的赋值运

10、算符%= return 0;【案例2-10计算不同数据类型的存储容量sizeof运算符#include using namespace std ;int main() cout The size of an int is:tt sizeof(int) bytes. n;cout Thesizeof a short int is:t sizeof(short) bytes. ncout Thesizeof a long int is:t sizeof(long) bytes. n;cout Thesizeof a char is:tt sizeof(char) bytes. n;cout The

11、sizeof a wchar_t is:t sizeof (wchar_t) 、 bytes. nz/cout Thesizeof a float is:tt sizeof(float) bytes. n;cout The return 0;sizeof a double is:t sizeof(double) bytes. n;【案例2-11巧妙获取整数部分double和int数据类型的转换#include using namespace std;int main () int nn=10, mm;double xx=4. 741, yy;cout nn*xx = nn*xx endl;表达

12、式类型转换mm=xx; yy=nn;赋值类型转换coutmm=mmendl yy二yyendl;coutint(xx)=int(xx)endl (int)xx=(int)xxendl; 强制类型转换 coutint(1. 412+xx) =int(l. 412+xx)endl; 强制类型转换 cout (int) 1. 412+xx= (int) 1. 412+xxendl; 强制类型转换 return 0;【案例2-12】将分数转换为小数强制类型转换#include using namespace std;int main() for( int i二1; i 二 5; +i )强制类型转换排

13、除除数为零的情况cout i / 3 is: (float) i / 3 endl;return 0;【案例2T3】安全的除法计算器#include using namespace std;int main () int a, b;cout Enter numerator: ; cin a;cout Enter denominator: ; cin b;if(b) cout Divide Result is: a / b 、n; else cout Divide by zero!n;return 0;【案例2-14】猜数游戏嵌套的if条件语句#include #include using na

14、mespace std; int main() int MagNum, GueNum;MagNum = rand(); 产生随机数cout GueNum; if (GueNum = MagNum) /if语句块起始位置cout * It is Right *n MagNum MagNum)cout “Guessed number is too high. n; elsecout Guessed number is too low. n;/else语句块结束位置return 0;【案例2T5】根据输入月份输出从年初到本月底的天数不带break的switchinclude using namesp

15、ace std;int main () int year, month, days=0;coutInput year and month:; cinyearmonth;switch(month)每个case分支均没有break语句 case12: days5 +=31;case11: days+=30;case10: days+=31;case9: days+=30;case8: days+=31;case7: days+=31;case6: days+=30;case5: days+=31;case4: days+=30;case3: days+=31;case2:判断是否为闰年if (ye

16、ar % 4=0 & year % 100!=0 year %400=0)days+=29;elsedays+=28;case1: days+=31;if (days=0) cout Wrong monthendl;else cout Total days is: days endl;return 0;【案例2-16计算数的阶乘do-while循环语句ttinclude using namespace std;int main() long limits;cout /Enter a positive integer:cin 1imits;cout ”Factorial numbers of 0

17、 is lendl; cout Factorial numbers of 1 is lendl; long fac=l, i=l;do 使用do-while循环 fac *= +i;cout Factorial numbers of ”i is facendl; while (fac limits);return 0;【案例2-17计算数的阶乘for循环include using namespace std;int main () long limits;cout Enter a positive integer: ; cin limits; cout Factorial numbers of

18、 is lendl; cout Factorial numbers of 1 is lendl; long fac=l;for (int i=2; fac=limits; i+) 使用 for 循环 fac *= i;cout *Factorial numbers of i is facendl; )return 0;【案例2-18I筛选素数步长为2的for循环include #include using namespace std;int mainO long n;cout Enter a positive integer: ; cin n;if (n 2)cout n is not pri

19、me. endl;else if (n 4)cout n is prime. endl;else if (n%2 = 0)cout n = 2* n/2 endl;else for (int i=3; i = n/2; i += 2) 步长为 2if (n%i = 0)cout n = i n/i endl; exit(0);cout n is prime. endl;)return 0;【案例2-19输出20之间的偶数continue语句include using namespace std;int main () cout Fhe even numbers are as follows:*

20、endl;for(int i=0; i=20; i+) if(i%2) continue; 根据条件使用continue结束本次循环 cout i * ;)return 0;)【案例2-20统计输入整数的个数并求和exit。函数#include #include using namespace std;int main () int sum=0, num=0, m;cout/Please input integers (0: end):，zendl;do cinm; num+;sum+=m;if(m=0) cout“Entered numbers: num integers. n;coutTh

21、e sum is:sumendl;exit(0); /使用exit ()函数终止程序)while(l);return 0;【案例2-21】“剪刀、石头、布”游戏枚举类型#include using namespace std;enum Choice ROCK, CLOTH, SCISS; 声明枚举类型 Choiceenum Winner Playl, Play2, Tie;声明枚举类型 Winnerint main () int n;Choice chol, cho2;Winner winner;cout Choose rock (0), cloth (1), or Sciss (2): en

22、dl;cout Player No. 1: cin n; chol = Choice(n);cout n; cho2 = Choice(n);if (chol = cho2) winner = Tie;else if (chol = ROCK)if (cho2 = CLOTH) winner = Play2;else winner = Playl;else if (chol = CLOTH)if (cho2 = SCISS) winner = Play2;else winner = Playl;elseif (cho2 = ROCK) winner = Play2;else winner =

23、Playl;if (winner = Tie) cout ”tTied!n;else if (winner = Playl) cout tPlayer No. 1 wins. endl;else cout *tPlayer No. 2 wins. endl; return 0;【案例2-22】简单的学生信息类型结构体#include #include using namespace std;struct student学生信息结构体 int num;char name20;char gender;int age;stul=1001, Zhang San, M, 19;int main () s

24、tudent stu2=1002, Li Si,，M,20); 声明结构体变量并初始化student stu3=1003, Wang Hong,22;声明结构体变量并初始化coutsetw(7)stul. numsetw(20) stul. namesetw(3)stul. gendersetw(3)stul. agee ndl;coutsetw (7) stu2. numsetw(20) stu2. namesetw(3) stu2. gendersetw(3)stu2. ageendl; coutsetw(7) stu3. numsetw(20) stu3. namesetw(3) stu

25、3. gendersetw(3) stu3. ageendl; return 0;【案例2-23】综合案例百钱买百鸡问题#includeusing namespace std;int mainOint n=100;cout鸡公 鸡母 鸡雏endl;/i表示鸡公,j表示鸡母,k表示鸡雏for ( inti=1;i=n;i+)for ( intj=1;j=n;j+)for( intk=1;k=n;k+)if( n=5*i+3*j+k/3)&(k%3=0)&(n=i+j+k) cout i j k endl;return 0;#include int main ()int x, y, z, j=0;

26、printf(Folleing are possible plans to buy 100 fowls with 100 Yuan. n);for(x=0;x=20;x+)for (y=0;y=33;y+)z=100-x-y;外层循环控制鸡翁数内层循环控制鸡母数y在、33变化内外层循环控制下,鸡雏数z的值受x,y的值的制约if (z%3=0&5*x+3*y+z/3=100)验证取z值的合理性及得到组解的合理性printf(*%2d:cock=%2d hen=%2d chicken=%2dn*, +j, x, y, z);【案例3-1】编写输出专用函数无参函数#include using nam

27、espace std;void DispMessage(void)cout“This is a Message!endl;)int mainODispMessageO ;return 0;)【案例3-2】编写求和函数有参函数#includeusing namespace std;double add(double x,double y)double z; z=x+y; return(z);)int mainOdouble a=0. 5, b=l. 0;coutadd(a, b)=add(a, b)endl;return 0;)【案例3-3】编写求和函数#include定义无参函数调用无参函数D

28、ispMessage定义有参函数调用有参函数add()函数的不同调用形式using namespace std;函数的定义,其有返回值double add(double x,double y)double z; z=x+y;coutx+y=zendl;return (z);int main ()double a=0. 5, b=l. 0;以不同参数形式调用函数add()coutadd(l. 5, 2. 5)=add(l. 5, 2. 5) endl;coutadd (a, b) =add (a, b)endl;以表达式方式调用函数add()以语句方式调用函数add() 以函数参数形式调用函数a

29、dd()cout”add(2*a, a+b)二add(2*a, a+b)endl;double c=2*add(a,b);coutc二cendl;add (2*a, b);cout add (a, add (a, b) =add (a, add (a, b)endl;return 0;【案例3-4编写符号函数函数的返冋值#include using namespace std; int sgn(double x) if (x0) return(1);if (x0) return(-1);return (0);) int mainO double x;for (int i二;i=2;i+)定义符

30、号函数sgn(),其返回值为int类型返回出口 1返回出口 2返回出口 3cout“Input x=；cinx;coutsgn (x)=”sgn (x) endl;)return 0;)【案例3-5】编写最值函数函数原型声明#includeusing namespace std;函数原型声明语句也可以在这里 int mainOfloat max(float, float);float a, b, Max;cout* Input a二;cina;cout Input ;cinb;Max二max (a, b);coutmax(a, by)?x:y; return (z);【案例3-6】值传递和引用

31、传递的区别#include using namespace std;void fun(int, int&);max()函数原型声明语句 变量声明语句输入参数a/输入参数b调用max ()函数返回值类型为浮点型函数参数一个为值传递,个引用传递int main ()(int a 二 22, b 二 44;cout Initial a = * a , b = b endl;fun(a, b); cout After fun(a, b), a 二 a ，b = b endl;fun(2*a-3, b); cout After fun(2*a-3,b), a = a , b = b endl;retur

32、n 0;void fun(int x, int& y) x = 88; y = 99; )【案例3-7编写最值函数内联函数#include using namespace std; inline int max(int x, int y)使用inline关键字声明max()为内联函数return xy?x:y;)int main()int a=3, b=5, c;c=max(a, b);coutmax(a，b)=cendl;coutmax(15， 11“)=max(15, 11)endl;return 0;)【案例3-8计算圆的面积和周长函数通过引用返回多于1个的数值#include usin

33、g namespace std; void ComCircle(double&, double&, double);函数的原型声明int main () double r, a, c;cout Enter radius: *; cin r;ComCircle (a, c, r);cout The area = a , and the circumference = c endl;return 0;)void ComCirc 1 e(doub 1 e& area, double& circum, double r)通过引用变量返回面积和周长(const double PI = 3. 141592

34、653589793;area = PI*r*r; circum = 2*PI*r;计算面积和周长【案例3-9】最小公倍数函数函数的嵌套调用#include using namespace std; long int gcd(long int m, long int n)求最大公约数if (m 0) int r = m%n; m = n; n = r;return m;long int lcm(long int m, long int n)求最小公倍数(return m*n/gcd(m, n);int main ()(int m, n;cout 、 Please input two intege

35、rs:cin m n;cout m ， n )= 1cm (m, n) endl;return 0;)【案例370】显示函数的参数带默认参数的函数include using namespace std;带有默认参数值的函数void disp(int x=l, int y=l, int z=l)cout z Parameter coutz* Parameter coutz Parameteris: xendl;2 is: yendl;is: zendl;int main ()cout No actualparameter endl;disp();disp(l);disp(l, 2);disp(l

36、, 2, 3);main()函数中测试参数带有默认值的函数disp()cout0ne actual parameterendl; cout Iwo actual parameterendl; coutThree actual parameterendl;return 0;)【案例3T1】通用最值函数参数数目可变的函数#include #include using namespace std;int max (int, int.):原型声明int mainO (int a, b, c, d, e;cout Enter five integers, seperate with space:; ci

37、nabcde;cout“The maxmum in a and b is: max (2, a, b) endl;coutThe maxmum in five integers is:max(5, a, b, c, d, e)n)va_end(ap);return n;)【案例372】多变的最值函数参数数目不同的重载函数include using namespace std;int main()int min (int a, int b, int c):函数声明int min (int a, int b):函数声明int il , i2, i3, i;cout“Enter three integers:; cin il i2 i3;输入 3 个整数i = min(il , i2) ; cout The min in two intergers= i endl;/ 2 个整数中最小者i = min(il ,i