完整C++经典代码大全推荐文档.docx
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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
constfloatPl=3.1416;//声明常量(只读变量)PI为3.1416
floatfCir_L(float);〃声明自定义函数fCir_L()的原型
floatfCir_S(float);//声明自定义函数fCir_S()的原型
//以下是main()函数main()
{
floatr,l,s;
//声明3个变量
doublel;l=2*3.1416*r;coutvv"l="vv|vvendl;
doubles=3.1416*r*r;coutvv"s="vvsvvendl;
//计算圆的周长,赋值给变量l
//显示圆的周长
//计算圆的面积,赋值给变量s
//显示圆的面积
cout>r;l=fCir_L(r);s=fCir_S(r);coutvv"l="vv|;cout}
〃显示字符串
//键盘输入
//计算圆的周长,赋值给变量l
//计算圆的面积,赋值给变量s
//显示计算结果
coutvv"R=";
cin>>r;
l=2*3.1416*r;coutvv"l="vv|vvendl;s=3.1416*r*r;coutvv"s="vvsvvendl;
//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
}
#includeviostream.h>//包含iostream.h头文件
//定义计算圆的周长的函数floatfCir_L(floatx)
{
floatz=-1.0;
if(x>=0.0)z=2*PI*x;
return(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()
floatfCir_S(floatx)
{
floatz=-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.CPP
Writtenby:
Hap
Datewritten:
02:
11:
10
*/
#includeviostream.h>
voidmain(void)
{
doubles1,s2,s3;
s1=1.5;/*对变量s1赋值*/
coutvv"s1="vvs1vvendl;
/*对变量s2赋值*/s2=2.5;
coutvv"s2="vvs2vvendl;
s3=/*对变量s3赋值*/3.5;
coutvv"s3="vvs3vvendl;
coutvv"s1+s2+s3="vvs1+s2+s3vvendl;//计算并显
示
〃计算并显示coutvv"s1+s2+s3="vvs1+s2+s3vvendl;
}
#includeviostream.h>
main()
doubler=1.0;coutvv"r="vvrvvendl;
voidmain()
{
//输岀字符常量、变量和字符串
charc1='A:
coutvv'W;
coutvvc1vvendl;coutvv"Thisisatest."vvendl;coutvv""vvendl;
//输岀整型常量、变量和表达式
intn=100;
coutvv10;
coutvvn;
cout«2*nvvendl;//输出整型表达式
coutvv""vvendl;
〃输岀浮点型常量、变量和表达式
doublepi=3.1415926,r=10.0,s=pi*r*r;
coutvvpivvendl;
coutvvr;
coutvvs;
cout«2*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;
coutvv"Thisisatest."vvendl;coutvv"pi="vvpivv"r="vvrvv"s="vvsvvendl;
}
#includeviostream.h>〃包含iostream.h头文件
main()
{
//输入输岀字符
charc;
cin>>c;
coutvv"c="vvcvvendl;
//输入输岀整型数据
intn;
cin>>n;
coutvv"n="vvnvvendl;
//输入输岀浮点型数据doublex;
cin>>x;coutvv"x="vvxvvendl;
//输入提示
coutcin»n;
cout〃多项输入
coutvv"cnx"vvendl;
cin>>c»n»x;coutvv"c="vvcvv"n="vvnvv"x="vvxvvendl;
}
#includeviostream.h>〃包含iostream.h头文件
main()
{
//声明整型变量
inta,b;
//从键盘上为整型变量赋值
coutvv"a=";
cin>>a;
coutvv"b=";
cin>>b;
//整型数的算术运算
coutvvavv"+"vvbvv"="vva+bvvendl;coutvvavv"-"vvbvv"="vva-bvvendl;coutvvavv"*"vvbvv"="vva*bvvendl;coutvvavv"/"vvbvv"="vva/bvvendl;
coutvvavv"%"vvbvv"="vva%bvvendl;
〃测试溢岀
shortn=32767,m;//n取short类型的最大值
coutvv"n="vvnvvendl;
m=n+1;//引起溢出
coutvv"n+1="vvmvvendl;
}
#includeviostream.h>〃包含iostream.h头文件
main()
{
//声明变量,并初始化
inta=010,b=10,c=0X10;
〃以十进制形式显示数据
coutvv"DEC:
";
coutvv"a="vva;
coutvv"b="vvb;
coutvv"c="vvcvvendl;
〃以八进制形式显示数据
coutvv"OCT:
";
coutvvoct;〃指定八进制输出
coutvv"a="vva;
coutvv"b="vvb;
coutvv"c="vvcvvendl;
〃以十六进制形式显示数据
coutvv"HEX:
";
coutvvhex;//指定十六进制输出
coutvv"a="vva;
coutvv"b="vvb;
cout«"c="v〃八、十和十六进制数混合运算并输岀
coutvv"a+b+c=";
coutvvdec;〃恢复十进制输出
coutvva+b+cvvendl;
〃测试八、十和十六进制输入
coutvv"DEC:
a=";cin>>a;
coutvv"OCT:
b=";cin>>b;
coutvv"HEX:
a=";cin>>c;
coutvv"DEC:
"vvdecvvendl;//指定十进制输出
coutvv"a="vvavvendl;
coutvv"b="vvbvvendl;coutvv"c="vvcvvendl;
}
#includeviostream.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
floatfx,fy;
coutvv"fx=";
cin>>fx;
coutvv"fy=";
cin>>fy;coutvvfxvv"+"vvfyvv"="vvfx+fyvvendl;coutvvfxvv"-"vvfyvv"="vvfx-fyvvendl;coutvvfxvv"*"vvfyvv"="vvfx*fyvvendl;coutvvfxvv"/"vvfyvv"="vvfx/fyvvendl«endl;
//coutvvfxvv"%"vvfyvv"="vvfx%fyvvendl;Error!
//double型变量的声明、输入、计算和输出
floatdx,dy;
coutvv"dx=";
cin>>dx;
coutvv"dy=";
cin>>dy;coutvvdxvv"+"vvdyvv"="vvdx+dyvvendl;coutvvdxvv"-"vvdyvv"="vvdx-dyvvendl;coutvvdxvv"*"vvdyvv"="vvdx*dyvvendl;coutvvdxvv"/"vvdyvv"="vvdx/dyvvendlvvendl;
//coutvvfxvv"%"vvfyvv"="vvfx%fyvvendl;Error!
〃测试float和double类型数据的有效位
fx=10.0;fy=6.0;
floatfz=fx/fy;
dx=10.0;dy=6.0;
doubledz=dx/dy;
coutvv"fz=";
coutvvsetprecision(20)vvfxvv"/"vvfyvv"="vvfzvvendl;coutvv"dz=";
coutvvsetprecision(20)vvdxvv"/"vvdyvv"="vvdzvvendlvvendl;;
//float型溢出
floatx=3.5e14;
coutvv"x="vvxvvendl;coutvv"x*x="vvx*xvvendl;
cout}
#includeviostream.h>〃包含iostream.h头文件
main()
{
〃字符类型变量的声明
charc1='A:
charc2;
//字符数据的运算及输岀
c2=c1+32;coutvv"c1="vvc1vvendl;coutvv"c2="vvc2vvendl;
//输出字符及ASCII码
coutvvclvv":
"vvint(c1)vvendl;
coutvvc2vv":
"vvint(c2)vvendl;coutvv'$'vv":
"vvint('$')vvendl;
//输入字符
coutvv"c1c2"vvendl;
cin»c1»c2;coutvv"c1="vvc1vv"c2="vvc2vvendl;
}
#includeviostream.h>〃包含iostream.h头文件
main()
{
charc1='\a',TAB='\t';
〃阵铃一声
coutvvclvvendl;
//使用水平制表符
C0utvv1vvTABvv2vvTABvv3vvTABvv4vvendl;
〃使用双引号
coutvv"Hesaid\"Thankyou\"."vvendl;
//使用回车换行coutvv"abc\n"vv"def"vv'\n';
}
#includeviostream.h>〃包含iostream.h头文件
main()
{
//声明bool变量,并初始化
boolflag1=false,flag2=true;
//输岀布尔常量和变量coutvv"false:
"vvfalsevvendl;
coutvv"true:
"vvtruevvendl;coutvv"flag1="vvflag1vvendl;coutvv"flag2="vvflag2vvendl;
//布尔变量的赋值和输岀
intx=1;
flag仁x>0;//存放关系运算结果
coutvv"flag1="vvflag1vvendl;
flag2=flag1;//bool类型变量相互赋值coutvv"flag2="vvflag2vvendl;
〃布尔变量超界处理
flag1=100;
coutvv"flag1="vvflag1vvendl;
flag2=-100;
coutvv"flag2="vvflag2vvendl;
}
#includeviostream.h>
constdoublePl=3.1416;//声明常量(const变量)PI为3.1416
main()
{
〃声明3个变量
doubler,l,s;
//输入圆的半径
coutvv"r=";
cin>>r;
//计算圆的周长
l=2*PI*r;
coutvv"l="vv|vvendl;
//计算圆的面积
s=PI*r*r;coutvv"s="vvsvvendl;
}
#includeviostream.h>
main()
{
//定义枚举类型,并指定其枚举元素的值enumcolor{
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
enumcolora=RED;
colorb;//合法,与C语言不同
//输出枚举常量
coutvv"RED="vvREDvvendl;coutvv"YELLOW="vvYELLOWvvendl;coutvv"BLUE="vvBLUEvvendl;
//枚举变量的赋值和输岀
b=a;
a=BLUE;
coutvv"a="vvavvendl;
coutvv"b="vvbvvendl;
〃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
coutvv"avb="vv(avb)vvendl;
}
#includeviostream.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=6.5
"vvendl;
inta=3,b=2;
//计算显示
(1)b+=a+2*c%5;的结果
constdoublePl=3.1416;main()
{
〃声明3个变量
doubler=3,l,s;
〃计算圆的周长
l=2*p|*r;cout〃计算圆的面积
s=PI*r*r;cout〃验证赋值误差
intil,is;
il=l;
is=s;
coutvv"il="vvilvvendl;coutvv"is="vvisvvendl;
}
#includeviostream.h>main()
{
〃变量声明
charc;
doublex,y;
〃测试自增
coutvv"++EandE++:
"vvendl;c='B';
coutvv"c="vv++cvvendl;c='B';
coutvv"c="vvc++vvendl;x=1.5;
y=5+++x;coutvv"y="vvyvvendl;x=1.5;
y=5+x++;coutvv"y="vvyvvendl;coutvv"
//测试自减
coutvv"--EandE--:
"vvendl;c='B';
coutvv"c="vv--cvvendl;//输出c=A
c='B';
coutvv"c="vvc--vvendl;//输出c=B
x=1.5;
y=5+--x;
coutvv"y="vvyvvendl;〃输出y=5.5
x=1.5;
y=5+x--;
coutvv"y="vvyvvendl;〃输出y=6.5
}
#includeviostream.h>main()
//输岀关系表达式
coutvvavbvvendl;coutvv(avb)vv(a>b)vv(a>=b)vv(a==b)vv(a!
=b)vvendl;
boolflag=2*avb+10;
coutvv"flag="vvflag;
}
#includeviostream.h>
main()
{
floata=3.5,b=2.1,c=0;
coutvv"a="vvavv"b="vvbvv"c="vvcvvendl;
//与运算
coutvv"a&&b="vv(a&&b)vvendl;〃输出1
coutvv"a&&c="vv(a&&c)vvendl;〃输出0
〃或运算
coutvv"a||b="vv(a||b)vvendl;〃输出1
coutvv"a||c="vv(a||c)vvendl;〃输出1
//非运算
coutvv"!
a="vv!
avvendlvv"!
c="vv!
cvvendl;〃输出01
//关系运算和逻辑运算
boolflag=a>=0&&av=5;//变量a在[0,5]区间内
coutvv"a=>0&&av=5="vvflagvvendl;〃输出1
//算术运算、关系运算和逻辑运算
coutvv"a+5>2*b+2||avb+3="vv(a+5>2*b+2||avb+3)vvendl;〃
输岀1
}
#includeviostream.h>
main()
{
//按位与运算
coutvv"24&12="vv(24&12)vvendl;
//按位异或运算
coutvv"24A12="vv(24A12)vvendl;
//按位或运算
coutvv"24|12="vv(24|12)vvendl;
//按位取反运算
coutvv"~24="vv(~24)vvendl;
//左移位运算
coutvv"5vv3="vv(5vv3)vvendl;
coutvv"-5vv3="vv(-5vv3)vvendl;
//右移位运算
coutvv"5>>3="vv(5>>3)vvendl;
coutvv"-5>>3="vv(-5>>3)vvendl;
}
#includeviostream.h>
main()
{
inta=1,b=1,c=3;
//显示a,b,c的值
coutvv"a="vvavv"b="vvbvv"c="vvcvvendl;
b+=a+2*c%5;//相当于表达式语句
b=b+(a+2*c%5);
cout«"
(1)b="v
〃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="v〃计算显示⑶a*=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="v〃计算显示⑷a+=b+=c;的结果
a=1,b=1,c=3;
a+=b+=c;//相当于语句组b=b+c;a=a+b;
coutvv"(4)a="vvavv"b="vvbvv"c="vvcvvendl;
〃计算显示(5)a-=b=++c+2;的结果
a=1,b=1,c=3;
a-=b=++c+2;//相当于语句组++c;b=b+c+2;a=a-b;
coutvv"(5)a="vvavv"b="vvbvv"c="vvcvvendl;
}
#includeviostream.h>
main()
{
〃用sizeof计算各类种常量的字节长度coutvv"sizeof('$')="vvsizeof('$')vvendl;
coutvv"sizeof
(1)="vvsizeof
(1)vvendl;coutvv"sizeof(1.5)="vvsizeof(1.5)vvendl;
coutvv"sizeof(\"Good!
\")="vvsizeof("Good!
")vvendl;
〃用sizeof计算各类型变量的字节长度
inti=100;
charc='A';
floatx=3.1416;
doublep=0.1;
coutvv"sizeof(i)="vvsizeof(i)vvendl;coutvv"sizeof(c)="vvsizeof(c)vvendl;coutvv"sizeof(x)="vvsizeof(x)vvendl;coutvv"sizeof(p)="vvsizeof(p)vvendl;
〃用sizeof计算表达式的字节长度
coutvv"sizeof(x+1.732)="vvsizeof(x+1.732)vvendl;
//用sizeof计算各类型的字节长度
coutvv"sizeof(char)="vvsizeof(char)vvendl;coutvv"sizeof(int)="vvsizeof(int)vvendl;
coutvv"sizeof(float)="vvsizeof(float)vvendl;coutvv"sizeof(double)="vvsizeof(double)vvendl;
〃用sizeof计算数组的字节长度
charstr[]="Thisisatest.";
inta[10];
doublexy[10];
coutvv"sizeof(str)="vvsizeof(str)vvendl;coutvv"sizeof(a)="vvsizeof(a)vvendl;coutvv"sizeof(xy)="vvsizeof(xy)vvendl;
//用sizeof计算自定义类型的长度
structst{
shortnum;
floatmath_grade;
floatChinese_grade;
floatsum_grade;
};
ststudentl;
coutvv"sizeof(st)="vvsizeof(st)vvendl;coutvv"sizeof(student1)="vvsizeof(student1)vvendl;
}
#includeviostream.h>
main()
{
〃声明变量语句中使用顺序运算
intx,y;
//计算中使用顺序运算
x=50;
y=(x=x-5,x/5);
coutvv"x="vvxvvendl;
coutvv"y="vvyvvendl;
}
#includeviostream.h>
main()
{
〃测试表达式类型的转换
intn=100,m;
doublex=3.791,y;
coutvv"n*x="vvn*x«endl;
//赋值类型转换
m=x;
y=n