C++经典程序代码大全.doc

//根据半径计算圆的周长和面积
#include
const float PI=3.1416; //声明常量(只读变量)PI为3.1416
float 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

cout<<"r="; //显示字符串
cin>>r; //键盘输入
l=fCir_L(r); //计算圆的周长，赋值给变量l
s=fCir_S(r); //计算圆的面积，赋值给变量s
cout<<"l="<//输出整型表达式
cout<<"------------------"<l;
cout<<"This is a test."<>c>>n>>x;
cout<<"c="< //指定十进制输出
cout<<"a="<";
cin>>fy;
cout<>c1>>c2;
cout<<"c1="< //包含iostream.h头文件
main()
{
//声明bool变量，并初始化
bool flag1=false,flag2=true;

//输出布尔常量和变量
cout<<"false:"<0 && a<=5="<2*b+2||a2*b+2||a
main()
{
//按位与运算
cout<<"24&12="<<(24&12)<>3="<<5>>3)<>3="<<(-5>>3)<
main()
{
int a=1,b=1,c=3;
//显示a,b,c的值
cout<<"a="<le p=0.1;
cout<<"sizeof(i)="<of(str)="<>a>>b; //利用cin从键盘上为变量 a,b 赋值
s=a;
if (a可省略花括号
}
s=s*s; //变量s中保存a,b中较大的一个数的平方
cout<<"s="<
main()
{
int x,y;
cout<<"x=";
cin>>x;
if (x<=0) { //满足条件执行
y=2*x;
cout<<"y="<x*x;
cout<<"y="<
main()
{
int a,b,c;
int smallest;
cout<<"a b c"<>a>>b>>c;
if (a<=b) //外层条件语句
{
if (a<=c) //内层条件语句
smallest=a;
else
smallest=c;
}
else
{
if (b<=c) //内层条件语句
smallest=b;
else
smallest=c;
}
cout<<"Smallest="<
main()
{
int score;

//从键盘上输入分数
cout<<"score=";
cin>>score;

//用带else if的条件语句判断处理
if (score<0 || score>100)
{
cout<<"The score is out of range!"<=90)
cout<<"Your grade is a A."<=80)
cout<<"Your grade is a B."<=70)
cout<<"Your grade is a C."< else if (score>=60)
cout<<"Your grade is a D."<
main()
{
int n;
cout<<"n=";
cin>>n;
if (n>=0 && n<=100 &&n%2==0)
cout<<"n="<ut of range!"<
main()
{
int a,b,Max;
//输入数据
cout<<"a=";
cin>>a;
cout<<"b=";
cin>>b;

//找出较大值
Max=a>b?a:b;
cout<<"Max="<
main()
{
int a,b;
//输入数据
cout<<"a=";
cin>>a;
cout<<"b=";
cin>>b;

//除法判断
if (b!=0 && a%b==0) {
cout<
main()
{
//x,y 为操作数，c为运算符
int x,y,z;