c--经典代码大全.doc

#include <iostream.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
cout<<"DEC:";
cout<<" a="<<a;
cout<<" b="<<b;
cout<<" c="<<c<<endl;

//以八进制形式显示数据
cout<<"OCT:";
cout<<oct; //指定八进制输出
cout<<" a="<<a;
cout<<" b="<<b;
cout<<" c="<<c<<endl;

//以十六进制形式显示数据
cout<<"HEX:";
cout<<hex; //指定十六进制输出
cout<<" a="<<a;
cout<<" b="<<b;
cout<<" c="<<c<<endl;

//八、十和十六进制数混合运算并输出
cout<<"a+b+c=";
cout<<dec; //恢复十进制输出
cout<<a+b+c<<endl;

//测试八、十和十六进制输入
cout<<"DEC:a="; cin>>a;
cout<<"OCT:b="; cin>>b;
cout<<"HEX:a="; cin>>c;
cout<<"DEC:"<<dec<<endl; //指定十进制输出
cout<<"a="<<a<<endl;
cout<<"b="<<b<<endl;
cout<<"c="<<c<<endl;
}
cin>>dx;
cout<<"dy=";
cin>>dy;
cout<<dx<<"+"<<dy<<"="<<dx+dy<<endl;
cout<<dx<<"-"<<dy<<"="<<dx-dy<<endl;
cout<<dx<<"*"<<dy<<"="<<dx*dy<<endl;
cout<<dx<<"/"<<dy<<"="<<dx/dy<<endl<<endl;
//cout<<fx<<"%"<<fy<<"="<<fx%fy<<endl; 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;
cout<<"fz=";
cout<<setprecision(20)<<fx<<"/"<<fy<<"="<<fz<<endl;
cout<<"dz=";
cout<<setprecision(20)<<dx<<"/"<<dy<<"="<<dz<<endl<<endl;;

//float型溢出
float x=3.5e14;
cout<<"x="<<x<<endl;
cout<<"x*x="<<x*x<<endl;
cout<<"x*x*x="<<x*x*x<<endl;
}

#include <iostream.h>
main()
{
//x,y 为操作数，c为运算符
int x,y,z;
char c1;
cin>>x>>c1>>y; //c1

//多路选择语句选择不同表达式计算语句
switch(c1) {
case '+':cout<<x<<"+"<<y<<"="<<x+y<<endl;
break;
case '-':cout<<x<<"-"<<y<<"="<<x-y<<endl;
break;
case '*':cout<<x<<"*"<<y<<"="<<x*y<<endl;
break;
case '/':cout<<x<<"/"<<y<<"="<<x/y<<endl;
break;
case '%':cout<<x<<"%"<<y<<"="<<x%y<<endl;
break;
default :cout<<"Wrong !"<<endl; //当不符合上述情况时执行本子句
}
}

#include<iostream.h>
float x=365.5; //声明全局变量
main() {
int x=1,y=2;
double w=x+y;
{
double x=1.414,y=1.732,z=3.14;
cout<<"inner:x="<<x<<endl;
cout<<"inner:y="<<y<<endl;
cout<<"inner:z="<<z<<endl;
cout<<"outer:w="<<w<<endl;
cout<<"::x="<<::x<<endl; //访问重名的全局变量
}
cout<<"outer:x="<<x<<endl;
cout<<"outer:y="<<y<<endl;
cout<<"outer:w="<<w<<endl;

//cout<<"inner:z="<<z<<endl;无效
cout<<"::x="<<::x<<endl; //访问重名的全局变量
}
#include<iostream.h>
main() {
//显示1,2,3...10
for(int i=1;i<=10;i++)
cout<<i<<" ";
cout<<endl;

//显示10,9,8...1
for(int j=10;j>=1;j--)
cout<<j<<" ";
cout<<endl;

//显示1,3,5...9
for(int k=1;k<=10;k=k+2)
cout<<k<<" ";
cout<<endl;

//显示ABC...Z
for(char c='A';c<='Z';c++)
cout<<c;
cout<<endl;

//显示0,0.1,0.2...1.0
for(float x=0;x<=1.0;x=x+0.1)
cout<<x<<" ";
cout<<endl;

//显示0,0.1,0.2...1.0
for(float x1=0;x1<=1.0+0.1/2;x1=x1+0.1)
cout<<x1<<" ";
cout<<endl;

//计算s=1+2+3...+100
int s=0;
for(int n=1;n<=100;n++)
s=s+n;
cout<<"s="<<s<<endl;
}
#include<iostream.h>
main()
{
//计算s=1+2+3...+100
int s=0,n=1;
while(n<=100) {
s=s+n;
n++;
}
cout<<"s="<<s<<endl;

//累加键盘输入的数据
double x,sum=0.0;
cout<<"x=";
cin>>x;
while(x!=0) {
sum+=x;
cout<<"x=";
cin>>x;
}
cout<<"sum="<<sum<<endl;
}
#include<iostream.h>
main()
{
//计算s=1+2+3...+100
int s=0,n=0;
do {
n++;
s+=n;
}while(n<100);
cout<<"s="<<s<<endl;

//累加键盘输入的数据
double x,sum=0.0;
do {
cout<<"x=";
cin>>x;
sum+=x;
} while(x!=0);
cout<<"sum="<<sum<<endl;
}

#include<iostream.h>
main()
{
//计算和打印打印乘法九九表
for (int i=1;i<=9;i++) {
cout<<i;
for (int j=1;j<=9;j++)
cout<<'\t'<<i<<"*"<<j<<"="<<i*j;
cout<<endl;
}
}

#include<iostream.h>
main()
{
int x,sum=0;
//定义标号L1
L1: cout<<"x=";
cin>>x;
if (x==-1)
goto L2; //无条件转移语句，转到L2语句处
else
sum+=x;
goto L1; //无条件转移语句，转到L1语句处
//定义标号L2
L2: cout<<"sum="<<sum<<endl;
}

#include<iostream.h>
main()
{
//累加键盘输入的数据
double x,sum=0.0;
while(1) {
cout<<"x=";
cin>>x;
if (x<=0) break;
sum+=x;
}
cout<<"sum="<<sum<<endl;
}

#include<iostream.h>
main()
{
int i;
for (i=1;i<=20;i++)
{
if (i%3==0) //能被 3 整除的整数，返回进行下次循环
continue;
cout<<i<<" ";
}
cout<<endl;
}
#include<iostream.h>
main()
{
//声明数组和变量
int a[5],i,sum;
double avg;

//从键盘上循环为数组赋值
for (i=0;i<5;i++) {
cout<<"a["<<i<<"]=";
cin>>a[i];
}

//直接显示数组元素
cout<<a[0]<<a[1]<<a[2]<<a[3]<<a[4]<<endl;

//利用for循环显示数组各元素的值
for (i=0;i<5;i++)
cout<<a[i]<<" ";
cout<<endl;

//计算数组元素之和,并显示计算结果
sum=a[0]+a[1]+a[2]+a[3]+a[4];
cout<<"sum="<<sum<<endl;

//利用循环计算数组的累加和
for (sum=0,i=0;i<5;i++)
sum+=a[i];

//显示累加和及平均值
cout<<"sum="<<sum<<endl;
avg=sum/5.0;
cout<<"avg="<<avg<<endl;
}
#include<iostream.h>
main()
{
int i,max,index,a[5];

//从键盘上为数组赋值
for (i=0;i<=4;i++)
{
cout<<"a["<<i<<"]=";
cin>>a[i];
}

// 利用循环遍历数组，找出最大值的元素及其下标
max=a[0];
for (i=0;i<=4;i++)
{
if (max<a[i])
{
max=a[i];
index=i;
}
}
cout<<"\nMax="<<max<<" index="<<index;
}
#include<iostream.h>
#define size 5
main()
{
//声明变量
int i,j;
float t,a[size];

//从键盘上为数组赋值
for (i=0;i<size;i++)
{
cout<<"a["<<i<<"]=";
cin>>a[i];
}

//对数组按从小到大顺序排序
for (i=0;i<size-1;i++)
for (j=i+1;j<size;j++)
if (a[i]>a[j])
{
t=a[i];
a[i]=a[j];
a[j]=t;
}

//显示排序结果
for (i=0;i<size;i++)
cout<<a[i]<<" ";
cout<<endl;

//输入要查找的数据
int value;
int found; //找到为1，否则为0
int low,high,mid;
for (i=1;i<=3;i++) {
cout<<"value=";
cin>>value;

//二分法查找数组a
found=0;
low=0;
high=size-1;
while(low<=high)
{
mid=(high+low)/2;
if (a[mid]==value)
{
found=1;
break;
}
if (a[mid]<value)
low=mid+1;
else
high=mid-1;
}
if (found)
cout<<"The valu found at:a["<<mid<<"]="<<a[mid]<<endl;
else
cout<<"The "<<value<<" is not found!"<<endl;
}
}
#include<iostream.h>
main()
{
//声明变量
int i,j;
float t,a[5];

//从键盘上为数组赋值
for (i=0;i<=4;i++)
{
cout<<"a["<<i<<"]=";
cin>>a[i];
}

//对数组按从大到小顺序排序
for (i=0;i<=3;i++)
for (j=i+1;j<=4;j++)
if (a[i]<=a[j])
{
t=a[i];
a[i]=a[j];
a[j]=t;
}

//显示排序结果
for (i=0;i<=4;i++)
cout<<a[i]<<" ";
}
#include<iostream.h>
main()
{
//声明二维数组及变量
int a[2][3],i,j;

//从键盘上为数组a赋值
for (i=0;i<2;i++)
for (j=0;j<3;j++)
{
cout<<"a["<<i<<"]["<<j<<"]=";
cin>>a[i][j];
}

//显示数组a
for (i=0;i<2;i++) {
for (j=0;j<3;j++)
{
cout<<a[i][j]<<" ";
}
cout<<endl;
}

//找出该数组的最大元素及其下标
int h,l,Max=a[0][0];
for (i=0;i<2;i++) {
for (j=0;j<3;j++)
{
if (Max<a[i][j]) {
Max=a[i][j];
h=i;
l=j;
}
}
}
cout<<"Max:"<<"a["<<h<<"]["<<l<<"]="<<a[h][l]<<endl;
}
#include<iostream.h>
main()
{
//声明字符数组和变量
char str[6];
int i;

//从键盘上输入字符串
cout<<"str=";
cin>>str;
cout<<str<<endl;

//按数组和下标变量两种方式显示字符数组
cout<<str<<endl;
for (i=0;i<6;i++)
cout<<str[i];
cout<<endl;

//字符串反向输出
for (i=5;i>=0;i--)
cout<<str[i];
cout<<endl;

//将字符数组变成大写字母后输出
for (i=0;i<=5;i++)
str[i]-=32; //小写字母转换成大写字母
cout<<str<<endl; //显示字符串
}
#include<iostream.h>
main()
{
//声明变量和指针变量
int a,b,c,*ip;

//指针变量ip指向变量a
a=100;
ip=&a; //使指针变量 ip 指向变量a
cout<<"a="<<a<<endl;
cout<<"*ip="<<*ip<<endl;
cout<<"ip="<<ip<<endl;

//指针变量ip指向变量b
ip=&b; //使指针变量 ip 指向变量b
b=200;
cout<<"b="<<b<<endl;
cout<<"*ip="<<*ip<<endl;
cout<<"ip="<<ip<<endl;

//指针变量ip指向变量c
ip=&c; //使指针变量 ip 指向变量b
*ip=a+b;
cout<<"c="<<c<<endl;
cout<<"*ip="<<*ip<<endl;
cout<<"ip="<<ip<<endl;
}
#include<iostream.h>
main()
{
//声明数组、变量和指针变量
int a[2][3],i,j;
int* ip;

//从键盘上为数组a赋值
for (i=0;i<2;i++) //为数组a赋值
for (j=0;j<3;j++)
{
cout<<"a["<<i<<"]["<<j<<"]=";
cin>>a[i][j];
}

//利用下标变量显示数组a
for (i=0;i<2;i++) {
for (j=0;j<3;j++)
{
cout<<a[i][j]<<" ";
}
cout<<endl;
}

//利用指针变量显示数组a
ip=&a[0][0];
for (i=0;i<2;i++) {
for (j=0;j<3;j++)
{
cout<<"a["<<i<<"]["<<j<<"]=";
cout<<ip<<" ";
cout<<*ip<<endl;
ip++;
}
}
}
#include<iostream.h>
main()
{
//声明数组、变量和指针变量
int a[]={1,2,3,4,5,6};
int *ip1,*ip2;

//测试指针的赋值运算
ip1=a;
ip2=ip1;
cout<<"*ip1="<<(*ip1)<<endl;
cout<<"*ip2="<<(*ip2)<<endl;

//测试指针的自增自减运算和组合运算
ip1++;
ip2+=4;
cout<<"*ip1="<<(*ip1)<<endl;
cout<<"*ip2="<<(*ip2)<<endl;

//测试指针变量之间的关系运算
int n=ip2>ip1;
cout<<"ip2>ip1="<<n<<endl;
cout<<"ip2!=NULL="<<(ip2!=NULL)<<endl;

//指针变量之间的减法
n=ip2-ip1;
cout<<"ip2-ip1="<<n<<endl;
}
#include<iostream.h>
main()
{
//声明字符型数组和指针变量
char str[10];
char *strip=str;

//输入输出
cout<<"str=";
cin>>str; //用字符数组输入字符串
cout<<"str="<<str<<endl;
cout<<"strip="<<strip<<endl;
cout<<"strip=";
cin>>strip; //用字符指针变量输入字符串
cout<<"str="<<str<<endl;
cout<<"strip="<<strip<<endl;

//利用指针变量改变其指向字符串的内容
*(strip+2)='l';
cout<<"str="<<str<<endl;
cout<<"strip="<<strip<<endl;

//动态为字符型指针变量分配内存
strip=new char(100);
cout<<"strip=";
cin>>strip; //用字符指针变量输入字符串
cout<<"str="<<str<<endl;
cout<<"strip="<<strip<<endl;
}
#include<iostream.h>
main()
{
// 声明用于存放运动员号码的数组
int h[]={1001,1002,1003,1004};
// 声明用于存放运动员成绩的数组
float x[]={12.3,13.1,11.9,12.1};
//声明用于存放运动姓名的字符型指针数组
char *p[]={"Wang hua","Zhang jian","Li wei","Hua ming"};
//i,j,it是用做循环控制变量和临时变量
int i,j,it;
//ft 用做暂存变量
float ft;
//pt为字符型指针变量用做暂存指针变量
char *pt;

//用选择法对数组x进行排序，并相应调整数组h和p中的数据
for (i=0;i<=3;i++)
for (j=i+1;j<=3;j++)
if (x[i]>=x[j]) {
ft=x[i],x[i]=x[j],x[j]=ft;
it=h[i],h[i]=h[j],h[j]=it;
pt=p[i],p[i]=p[j],p[j]=pt;
}

//以下打印排序结果
for (i=0;i<=3;i++)
cout<<h[i]<<" ,"<<p[i]<<" ,"<<x[i]<<endl;
}
#include<iostream.h>
main()
{
//声明指针数组
char *colors[]={"Red","Blue","Yellow","Green"};
//指向指针的指针变量
char **pt;

//通过指向指针的变量访问其指向的内容
pt=colors;
for (int i=0;i<=3;i++) {
cout<<"pt="<<pt<<endl;
cout<<"*pt="<<*pt<<endl;
cout<<"**pt="<<**pt<<endl;
pt++;
}
}
#include<iostream.h>
main()
{
//定义结构类型
struct books
{
char title[20];
char author[15];
int pages;
float price;
} ;

//声明结构变量
struct books Zbk={"VC++ ","Zhang",295,35.5};
books Wbk;

//对结构变量的输出
cout<<"Zbk:"<<endl;
cout<<Zbk.title <<endl;
cout<<Zbk.author<<endl;
cout<<Zbk.pages<<endl;
cout<<Zbk.price<<endl;
cout<<"--------------------"<<endl;

//对结构成员的运算
Zbk.pages+=10;
Zbk.price+=0.5;
cout<<"Zbk.pages="<<Zbk.pages<<endl;
cout<<"Zbk.price="<<Zbk.price<<endl;
cout<<"--------------------"<<endl;

//对结构变量的输入输出
cout<<"Wbk.title =";
cin>>Wbk.title;
cout<<"Wbk.author=";
cin>>Wbk.author;
cout<<"Wbk.pages=";
cin>>Wbk.pages;
cout<<"Wbk.price=";
cin>>Wbk.price;
cout<<"Wbk:"<<endl;
cout<<Wbk.title <<endl;
cout<<Wbk.author<<endl;
cout<<Wbk.pages<<endl;
cout<<Wbk.price<<endl;
cout<<"--------------------"<<endl;

//结构变量之间的相互赋值
books temp;
temp=Wbk;
cout<<"temp:"<<endl;
cout<<temp.title<<endl;
cout<<temp.author<<endl;
cout<<temp.pages<<endl;
cout<<temp.price<<endl;
}

#include<iostream.h>
main()
{
int i;
//定义结构类型
struct student {
int num;
char name[10];
float maths;
float physics;
float chemistry;
double total;
};

//声明结构数组st
student st[3];

//从键盘上为结构数组输入值
cout<<" num name maths physics chemistry "<<endl;
for (i=0;i<3;i++)
{
cout<<i+1<<" ";
cin>>st[i].num;
cin>>st[i].name;
cin>>st[i].maths;
cin>>st[i].physics;
cin>>st[i].chemistry;
}

//计算每个学生的总成绩
for (i=0;i<3;i++)
st[i].total=st[i].maths+st[i].physics+st[i].chemistry;

//输出结构数组各元素的值
for (i=0;i<3;i++)
{
cout<<"st["<<i<<"]: ";
cout<<st[i].num<<'\t';
cout<<st[i].name<<'\t';
cout<<st[i].maths<<'\t';
cout<<st[i].physics<<'\t';
cout<<st[i].chemistry<<'\t';
cout<<st[i].total<<endl;
}
}
#include<iostream.h>
main()
{
//定义结构类型
struct human {
char name[10];
int sex;
int age;
};

//声明结构变量和结构指针变量,并初始化
struct human x={"WangPing",1,30},*p=NULL;

//结构指针变量指向对象
p=&x;

//显示结构变量的值
cout<<"x.name="<<x.name<<endl;
cout<<"x.sex="<<x.sex<<endl;
cout<<"x.age="<<x.age<<endl;

//利用结构指针显示结构对象中的数据
cout<<"(*p).name="<<(*p).name<<endl;
cout<<"(*p).sex="<<(*p).sex<<endl;