C++典型案例分析.doc

C+简单程序典型案例【案例2-1】设计一个编写仅包含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 age; /声明一个变量 age= 20; /赋值语句 coutThe age is:n; /输出一个字符串 coutageendl; /输出变量中的值return 0; /主函数返回0/块作用域结束 【案例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 r=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*PI*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】整数的简单运算除法、求余运算法和增量减量运算符#include using namespace std; int main() 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2-4】多重计数器前置和后置自增运算符#includeusing namespace std;int main()int iCount=1;iCount=(iCount+)+(iCount+)+(iCount+);/后置+coutThe first iCount=iCountendl;iCount=1;iCount=(+iCount)+(+iCount)+(+iCount);/前置+coutThe second iCount=iCountendl;iCount=1;iCount=-iCount+;/后置+coutThe third iCount=iCountendl;iCount=1;iCount=-+iCount;/前置+coutThe fourth iCount=iCountendl;return 0;【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;int main() cout 20&10= (20&10) endl;/按位与运算 cout 2010= (2010) endl;/按位异或运算 cout 20|10= (20|10) endl;/按位或运算 cout 20= (20) 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 3= 3) endl;/右移位运算 cout 3= 3) endl;/右移位运算return 0;【案例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 = 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 | q) & !(p & q) ) n; /输出异或结果p = false; q = 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 iNum1=1,iNum2,iMax;coutiNum1iNum2;iMax = iNum1iNum2 ? iNum1 : iNum2; /使用条件运算符构建条件表达式coutThe max integer is: iMaxendl; return 0;【案例2-8】“多计算与单提取”功能的实现逗号表达式#includeusing namespace std;int main() int Val1, Val2, Val3, Left, Midd, Righ;Left = 10;Midd = 20; Righ = 30; Val1 = (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 Val1=tVal1 nVal2=tVal2 nVal3=tVal3endl; return 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; cout After n += 8, n = n endl; /使用复合的赋值运算符+=n -= 6; cout After n -= 6, n = n endl; /使用复合的赋值运算符-=n *= 1; cout After n *= 1, n = n endl;/使用复合的赋值运算符*=n /= 4; cout After n /= 4, n = n endl; /使用复合的赋值运算符/=n %= 3; cout After n %= 3, n = n endl; /使用复合的赋值运算符%=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 The size of a short int is:t sizeof(short) bytes.n;cout The size of a long int is:t sizeof(long) bytes.n;cout The size of a char is:tt sizeof(char) bytes.n;cout The size of a wchar_t is:t sizeof(wchar_t) bytes.n;cout The size of a float is:tt sizeof(float) bytes.n;cout The size of a double is:t sizeof(double) bytes.n;return 0;【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; coutnn*xx=nn*xxendl; /表达式类型转换 mm=xx; yy=nn; /赋值类型转换 coutmm=mmendl yy=yyendl; coutint(xx)=int(xx)endl (int)xx=(int)xxendl; /强制类型转换 coutint(1.412+xx)=int(1.412+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=1; i = 5; +i ) cout i / 3 is: (float) i / 3 endl; /强制类型转换return 0; 【案例2-13】安全的除法计算器#include using namespace std; int main() int a, b; cout a; cout b; if(b) cout Divide Result is: a / b n; /排除除数为零的情况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 namespace 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 is the Magess number.n; /if语句块结束位置else / else语句块起始位置cout Sorry, youre wrong. MagNum) cout Guessed number is too high.n; else cout Guessed number is too low.n; /else语句块结束位置return 0; 【案例2-15】根据输入月份输出从年初到本月底的天数不带break的switch#include using namespace std;int main()int year,month,days=0;coutyearmonth;switch (month) /每个case分支均没有break语句 case 12: days +=31;case 11: days +=30; case 10: days +=31;case 9: days +=30;case 8: days +=31;case 7: days +=31;case 6: days +=30;case 5: days +=31;case 4: days +=30;case 3: days +=31; case 2: /判断是否为闰年if (year % 4=0 & year % 100!=0 | year %400=0) days +=29;else days +=28;case 1: 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#include using namespace std;int main() long limits; cout limits; cout Factorial numbers of 0 is 1endl; cout Factorial numbers of 1 is 1endl; long fac=1, i=1; 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 limits; cout Factorial numbers of 0 is 1endl; cout Factorial numbers of 1 is 1endl; long fac=1;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2-18】筛选素数步长为2的for循环#include #include using namespace std;int main()long n;cout n;if (n 2) cout n is not prime. endl;else if (n 4) cout n is prime. endl;else if (n%2 = 0) cout n = 2* n/2 endl;elsefor (int i=3; i = n/2; i += 2)/步长为2 if (n%i = 0) cout n = i * n/i endl; exit(0); cout n is prime. endl;return 0;【案例2-19】输出120之间的偶数continue语句#include using namespace std; int main() coutThe even numbers are as follows: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; coutPlease input integers (0:end):m; num+; sum+=m; if(m=0) coutEntered numbers:num integers.n;coutThe sum is:sumendl;exit(0);/ 使用exit()函数终止程序 while(1);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 Play1, Play2, Tie; /声明枚举类型Winnerint main()int n; Choice cho1, cho2; Winner winner;cout Choose rock (0), cloth (1), or Sciss (2): endl;cout n;cho1 = Choice(n);cout n;cho2 = Choice(n);if (cho1 = cho2) winner = Tie;else if (cho1 = ROCK)if (cho2 = CLOTH) winner = Play2;else winner = Play1;else if (cho1 = CLOTH)if (cho2 = SCISS) winner = Play2;else winner = Play1;else if (cho2 = ROCK) winner = Play2;else winner = Play1;if (winner = Tie) cout tTied!n;else if (winner = Play1) 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; stu1=1001,Zhang San,M,19;int main()student stu2=1002,Li Si,M,20;/声明结构体变量并初始化student stu3=1003,Wang Hong,F,22; /声明结构体变量并初始化 coutsetw(7)stu1.numsetw(20)setw(3)st