完整C++经典代码大全推荐文档.docx

1、完整C+经典代码大全推荐文档/根据半径计算圆的周长和面积#include const float Pl=3.1416; /声明常量(只读变量)PI 为 3.1416float fCir_L(float); 声明自定义函数fCir_L()的原型float fCir_S(float); /声明自定义函数 fCir_S()的原型/以下是main()函数 main()float r,l,s;/声明3个变量double l; l=2*3.1416*r; coutvvl=vv|vvendl;double s=3.1416*r*r; coutvvs=vvsvve ndl;/计算圆的周长，赋值给变量l/显示圆

2、的周长/计算圆的面积，赋值给变量 s/显示圆的面积coutr; l=fCir_L(r); s=fCir_S(r); coutvvl=vv|; coutvns=vr;l=2*3.1416*r; coutvvl=vv|vvendl; s=3.1416*r*r; coutvvs=vvsvve ndl;/显示提示输入的信息/键盘输入/计算圆的周长，赋值给变量l/显示圆的周长/显示圆的面积#include viostream.h /包含 iostream.h 头文件/定义计算圆的周长的函数 float fCir_L(float x)float z=-1.0;if (x=0.0) z=2*PI*x;ret

3、urn(z);fCir_L()声明局部变量/如果参数大于0,则计算圆的周长/返回函数值定义计算圆的面积的函数 fCir_S()float fCir_S(float x)float z=-1.0; /声明局部变量if (x=0.0) /如果参数大于0,则计算圆的面积z=PI*x*x;return(z); 返回函数值/* Program: P1-2.CPPWritten by: HapDate written: 02:11:10*/#include viostream.hvoid main(void)double s1,s2,s3;s1=1.5; /*对变量s1赋值*/coutvvs1=vvs1v

4、vendl;/*对变量s2赋值*/ s2=2.5;coutvvs2=vvs2vvendl;s3= /*对变量s3赋值*/ 3.5;coutvvs3=vvs3vvendl;coutvvs1+s2+s3=vvs1+s2+s3vvendl; / 计算并显示计算并显示 coutvvs1+s2+s3=vvs1+s2+s3vvendl;#include viostream.hmain()double r=1.0; coutvvr=vvrvve ndl;void main()/输岀字符常量、变量和字符串char c1=A： coutvvW;coutvvc1vvendl; coutvvThis is a te

5、st.vvendl; coutvv vvendl;/输岀整型常量、变量和表达式int n=100;coutvv10;coutvvn;cout2*nvvendl; /输出整型表达式coutvv vvendl;输岀浮点型常量、变量和表达式double pi=3.1415926,r=10.0,s=pi*r*r;coutvvpivvendl;coutvvr;coutvvs;cout2*r*pivvendl; 输出浮点型表达式coutvv vvendl;一个cout可以输出多项数据coutvvWvv vvc1vvendl;coutvvThis is a test.vvendl; coutvvpi=vvp

6、ivv r=vvrvv s=vvsvve ndl;#include viostream.h 包含 iostream.h 头文件main()/输入输岀字符char c;cinc;coutvvc=vvcvve ndl;/输入输岀整型数据int n;cinn;coutv vn=vvnvven dl;/输入输岀浮点型数据 double x;cinx; coutvvx=vvxvve ndl;/输入提示cout vn=;cinn;coutcnx; coutvvc=vvcvv n=vvnvv x=vvxvve ndl;#include viostream.h 包含 iostream.h 头文件main()/

7、声明整型变量int a,b;/从键盘上为整型变量赋值coutvva=;cina;coutvvb=;cinb;/整型数的算术运算coutvvavv+vvbvv=vva+bvve ndl; coutvvavv-vvbvv=vva-bvve ndl; coutvvavv*vvbvv=vva*bvve ndl; coutvvavv/vvbvv=vva/bvve ndl;coutvvavv%vvbvv=vva%bvvendl;测试溢岀short n=32767,m; /n 取 short 类型的最大值coutv vn=vvnvven dl;m=n+1; /引起溢出coutvvn+1=vvmvvendl;

8、#include viostream.h 包含 iostream.h 头文件main()/声明变量，并初始化int a=010,b=10,c=0X10;以十进制形式显示数据coutvvDEC:;coutvv a=vva;coutvv b=vvb;coutvv c=vvcvve ndl;以八进制形式显示数据coutvvOCT:;coutvvoct; 指定八进制输出coutvv a=vva;coutvv b=vvb;coutvv c=vvcvve ndl;以十六进制形式显示数据coutvvHEX:;coutvvhex; /指定十六进制输出coutvv a=vva;coutvv b=vvb;cout

9、 c=vca;coutvvOCT:b=; cinb;coutvvHEX:a=; cinc;coutvvDEC:vvdecvvendl; /指 定十进制输出coutvva=vvavve ndl;coutvvb=vvbvve ndl; coutvvc=vvcvve ndl;#include viostream.h 包含 iostream.h 头文件#includeviomanip.h / iomanip.h 头文件包含 setprecision()的 定义main()/float型变量的声明、输入、计算和输出float fx,fy;coutvvfx=;cinfx;coutvvfy=;cinfy;

10、coutvvfxvv+vvfyvv=vvfx+fyvve ndl; coutvvfxvv-vvfyvv=vvfx-fyvvendl; coutvvfxvv*vvfyvv=vvfx*fyvvendl; coutvvfxvv/vvfyvv=vvfx/fyvve ndle ndl;/coutvvfxvv%vvfyvv=vvfx%fyvvendl; Error!/double型变量的声明、输入、计算和输出float dx,dy;coutvvdx=;cindx;coutvvdy=;cindy; coutvvdxvv+vvdyvv=vvdx+dyvve ndl; coutvvdxvv-vvdyvv=vvd

11、x-dyvve ndl; coutvvdxvv*vvdyvv=vvdx*dyvve ndl; coutvvdxvv/vvdyvv=vvdx/dyvve ndlvve ndl;/coutvvfxvv%vvfyvv=vvfx%fyvvendl; Error!测试float和double类型数据的有效位fx=10.0;fy=6.0;float fz=fx/fy;dx=10.0;dy=6.0;double dz=dx/dy;coutvvfz=;coutvvsetprecisi on( 20)vvfxvv/vvfyvv=vvfzvve ndl; coutvvdz=;coutvvsetprecision(

12、20)vvdxvv/vvdyvv=vvdzvvendlvvendl;/float型溢出float x=3.5e14;coutvvx=vvxvve ndl; coutvvx*x=vvx*xvve ndl;cout 包含 iostream.h 头文件main()字符类型变量的声明char c1=A：char c2;/字符数据的运算及输岀c2=c1+32; coutvvc1=vvc1vvendl; coutvvc2=vvc2vvendl;/输出字符及ASCII码coutvvclvv : vvint(c1)vvendl;coutvvc2vv : vvint(c2)vvendl; coutvv$vv :

13、 vvint($)vvendl;/输入字符coutvvc1 c2vvendl;cinc1c2; coutvvc1=vvc1vv c2=vvc2vvendl;#include viostream.h 包含 iostream.h 头文件main()char c1=a,TAB=t;阵铃一声coutvvclvvendl;/使用水平制表符C0utvv1vvTABvv2vvTABvv3vvTABvv4vvendl;使用双引号coutvvHe said Thank you.vvendl;/使用回车换行 coutvvabcnvvdefvvn;#include viostream.h 包含 iostream.h

14、 头文件main()/声明bool变量，并初始化bool flag1=false,flag2=true;/输岀布尔常量和变量 coutvvfalse:vvfalsevvendl;coutvvtrue: vvtruevvendl; coutvvflag1=vvflag1vvendl; coutvvflag2=vvflag2vvendl;/布尔变量的赋值和输岀int x=1;flag仁x0; /存放关系运算结果coutvvflag1=vvflag1vvendl;flag2=flag1; /bool类型变量相互赋值 coutvvflag2=vvflag2vvendl;布尔变量超界处理flag1=10

15、0;coutvvflag1=vvflag1vvendl;flag2=-100;coutvvflag2=vvflag2vvendl;#include viostream.hconst double Pl=3.1416; /声明常量(const 变量)PI 为 3.1416main()声明3个变量double r,l,s;/输入圆的半径coutvvr=;cinr;/计算圆的周长l=2*PI*r;coutvvl=vv|vvendl;/计算圆的面积s=PI*r*r; coutvvs=vvsvve ndl;#includeviostream.hmain()/定义枚举类型，并指定其枚举元素的值 enum

16、color RED=3,YELLOW=6,BLUE=9;声明枚举变量a和b,并为枚举变量a赋初值enum color a=RED;color b; /合法，与C语言不同/输出枚举常量coutvvRED=vvREDvvendl; coutvvYELLOW=vvYELLOWvvendl; coutvvBLUE=vvBLUEvvendl;/枚举变量的赋值和输岀b=a;a=BLUE;coutvva=vvavve ndl;coutvvb=vvbvve ndl;a=100;错误！/a=6 也错误！/枚举变量的关系运算b=BLUE; /枚举变量的赋值运算coutvvavb=vv(avb)vve ndl;#i

17、nclude viostream.h/声明常量（const变量）PI为3.1416/输岀c=C/输岀c=B/加号后的空格不能少输出y=7.5输出y=6.5vvendl;int a=3, b=2;/计算显示（1） b+=a+2*c%5;的结果const double Pl=3.1416; main()声明3个变量double r=3,l,s;计算圆的周长l=2*p|*r; coutvl=vv|vendl;计算圆的面积s=PI*r*r; coutvs=v main()变量声明char c;double x,y;测试自增coutvv+E and E+ :vvendl; c=B;coutvvc=vv+

18、cvvendl; c=B;coutvvc=vvc+vvendl; x=1.5;y=5+ +x; coutvvy=vvyvve ndl; x=1.5;y=5+x+; coutvvy=vvyvve ndl; coutvv /测试自减coutvv-E and E- :vvendl; c=B;coutvvc=vv-cvvendl; /输出 c=Ac=B;coutvvc=vvc-vvendl; /输出 c=Bx=1.5;y=5+-x;coutvvy=vvyvvendl; 输出 y=5.5x=1.5;y=5+x-;coutvvy=vvyvvendl; 输出 y=6.5#include viostream.

19、h main()/输岀关系表达式coutvvavbvvendl; coutvv(avb)vv(ab)vv(a=b)vv(a=b)vv(a!=b)vvendl;bool flag=2*avb+10;coutvvflag=vvflag;#include viostream.hmain()float a=3.5,b=2.1,c=0;coutvva=vvavv b=vvbvv c=vvcvve ndl;/与运算coutvva&b=vv(a&b)vvendl; 输出 1coutvva&c=vv(a&c)vvendl; 输出 0或运算coutvva|b=vv(a|b)vvendl; 输出 1coutvva

20、|c=vv(a|c)vvendl; 输出 1/非运算coutvv!a=vv!avvendlvv!c=vv!cvvendl; 输出 0 1/关系运算和逻辑运算bool flag=a=0 & av=5; /变量 a 在0,5区间内coutvva=0 & av=5=vvflagvvendl; 输出 1/算术运算、关系运算和逻辑运算coutvva+52*b+2|avb+3=vv(a+52*b+2|avb+3)vvendl;输岀1#include viostream.hmain()/按位与运算coutvv24&12=vv(24&12)vvendl;/按位异或运算coutvv24A12=vv(24A12)

21、vvendl;/按位或运算coutvv24|12=vv(24|12)vvendl;/按位取反运算coutvv24=vv(24)vvendl;/左移位运算coutvv5vv3=vv(5vv3)vvendl;coutvv-5vv3=vv(-5vv3)vvendl;/右移位运算coutvv53=vv(53)vvendl;coutvv-53=vv(-53)vvendl;#include viostream.hmain()int a=1,b=1,c=3;/显示a,b,c的值coutvva=vvavv b=vvbvv c=vvcvve ndl;b+=a+2*c%5; /相当于表达式语句b=b+(a+2*c

22、%5);cout(1) b=vbve ndl;计算显示(2) a=c-2*b;的结果a=1,b=1,c=3;a=c-2*b; / 相当于表达式语句 a=a(c-2*b);cout(2) a=vave ndl;计算显示a*=b=c=3;的结果a=1,b=1,c=3;a*=b=c=3; / 相当于语句组 c=3;b=c;a=a*b;cout(3) a=vav b=vbv c=vcmain()用sizeof计算各类种常量的字节长度 coutvvsizeof($)=vvsizeof($)vvendl;coutvvsizeof(1)=vvsizeof(1)vvendl; coutvvsizeof(1.5

23、)=vvsizeof(1.5)vvendl;coutvvsizeof(Good!)=vvsizeof(Good!)vvendl;用sizeof计算各类型变量的字节长度int i=100;char c=A;float x=3.1416;double p=0.1;coutvvsizeof(i)=vvsizeof(i)vvendl; coutvvsizeof(c)=vvsizeof(c)vvendl; coutvvsizeof(x)=vvsizeof(x)vvendl; coutvvsizeof(p)=vvsizeof(p)vvendl;用sizeof计算表达式的字节长度coutvvsizeof(x

24、+1.732)=vvsizeof(x+1.732)vvendl;/用 sizeof计算各类型的字节长度coutvvsizeof(char)=vvsizeof(char)vvendl; coutvvsizeof(int)=vvsizeof(int)vvendl;coutvvsizeof(float)=vvsizeof(float)vvendl; coutvvsizeof(double)=vvsizeof(double)vvendl;用sizeof计算数组的字节长度char str=This is a test.;int a10;double xy10;coutvvsizeof(str)=vvsi

25、zeof(str)vvendl; coutvvsizeof(a)=vvsizeof(a)vvendl; coutvvsizeof(xy)=vvsizeof(xy)vvendl;/用sizeof计算自定义类型的长度struct st short num;float math_grade;float Chinese_grade;float sum_grade;st studentl;coutvvsizeof(st)=vvsizeof(st)vvendl; coutvvsizeof(student1)=vvsizeof(student1)vvendl;#include viostream.hmain()声明变量语句中使用顺序运算int x, y;/计算中使用顺序运算x=50;y=(x=x-5, x/5);coutvvx=vvxvve ndl;coutvvy=vvyvve ndl;#include viostream.hmain()测试表达式类型的转换int n=100,m;double x=3.791,y;coutv vn *x= vvn *xe ndl;/赋值类型转换m=x;y=n