C++ 实例 - 输出 "Hello, World!"

#include <iostream>

using namespace std;

int main()

{

    cout << "Hello, World!";

    return ;

}

C++ 实例 - 标准输入输出

#include <iostream>

using namespace std;

int main()

{

    int number;

    cout << "输入一个整数: ";

    cin >> number;

    cout << "输入的数字为: " << number;

    return ;

}

C++ 实例 - 实现两个数相加

#include <iostream>

using namespace std;

int main()

{

    int firstNumber, secondNumber, sumOfTwoNumbers;

    cout << "输入两个整数: ";

    cin >> firstNumber >> secondNumber;

    // 相加

    sumOfTwoNumbers = firstNumber + secondNumber;

    // 输出

    cout << firstNumber << " + " <<  secondNumber << " = " << sumOfTwoNumbers;     

    return ;

}

C++ 实例 - 求商及余数

#include <iostream>

using namespace std;

int main()

{

    int divisor, dividend, quotient, remainder;

    cout << "输入被除数: ";

    cin >> dividend;

    cout << "输入除数: ";

    cin >> divisor;

    quotient = dividend / divisor;

    remainder = dividend % divisor;

    cout << "商 = " << quotient << endl;

    cout << "余数 = " << remainder;

    return ;

}

C++ 实例 - 查看 int, float, double 和 char 变量大小

#include <iostream>

using namespace std;

int main()

{

    cout << "char: " << sizeof(char) << " 字节" << endl;

    cout << "int: " << sizeof(int) << " 字节" << endl;

    cout << "float: " << sizeof(float) << " 字节" << endl;

    cout << "double: " << sizeof(double) << " 字节" << endl;

    return ;

}

C++ 实例 - 交换两个数

#include <iostream>

using namespace std;

int main()

{

    int a = , b = , temp;

    cout << "交换之前：" << endl;

    cout << "a = " << a << ", b = " << b << endl;

    temp = a;

    a = b;

    b = temp;

    cout << "\n交换之后：" << endl;

    cout << "a = " << a << ", b = " << b << endl;

    return ;

}

C++ 实例 - 判断一个数是奇数还是偶数

#include <iostream>

using namespace std;

int main()

{

    int n;

    cout << "输入一个整数: ";

    cin >> n;

    if ( n %  == )

        cout << n << " 为偶数。";

    else

        cout << n << " 为奇数。";

    return ;

}

C++ 实例 - 判断元音/辅音

#include <iostream>

using namespace std;

int main()

{

    char c;

    int isLowercaseVowel, isUppercaseVowel;

    cout << "输入一个字母: ";

    cin >> c;

    // 小写字母元音

    isLowercaseVowel = (c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u');

    // 大写字母元音

    isUppercaseVowel = (c == 'A' || c == 'E' || c == 'I' || c == 'O' || c == 'U');

    // if 语句判断

    if (isLowercaseVowel || isUppercaseVowel)

        cout << c << " 是元音";

    else

        cout << c << " 是辅音";

    return ;

}

C++ 实例 - 判断三个数中的最大数

#include <iostream>

using namespace std;

int main()

{

    float n1, n2, n3;

    cout << "请输入三个数: ";

    cin >> n1 >> n2 >> n3;

    if(n1 >= n2 && n1 >= n3)

    {

        cout << "最大数为: " << n1;

    }

    if(n2 >= n1 && n2 >= n3)

    {

        cout << "最大数为: " << n2;

    }

    if(n3 >= n1 && n3 >= n2) {

        cout << "最大数为: " << n3;

    }

    return ;

}

C++ 实例 - 求一元二次方程的根

#include <iostream>

#include <cmath>

using namespace std;

int main() {

    float a, b, c, x1, x2, discriminant, realPart, imaginaryPart;

    cout << "输入 a, b 和 c: ";

    cin >> a >> b >> c;

    discriminant = b*b - *a*c;

    if (discriminant > ) {

        x1 = (-b + sqrt(discriminant)) / (*a);

        x2 = (-b - sqrt(discriminant)) / (*a);

        cout << "Roots are real and different." << endl;

        cout << "x1 = " << x1 << endl;

        cout << "x2 = " << x2 << endl;

    }

    else if (discriminant == ) {

        cout << "实根相同：" << endl;

        x1 = (-b + sqrt(discriminant)) / (*a);

        cout << "x1 = x2 =" << x1 << endl;

    }

    else {

        realPart = -b/(*a);

        imaginaryPart =sqrt(-discriminant)/(*a);

        cout << "实根不同："  << endl;

        cout << "x1 = " << realPart << "+" << imaginaryPart << "i" << endl;

        cout << "x2 = " << realPart << "-" << imaginaryPart << "i" << endl;

    }

    return ;

}

C++ 实例 - 计算自然数之和

#include <iostream>

using namespace std;

int main()

{

    int n, sum = ;

    cout << "输入一个正整数: ";

    cin >> n;

    for (int i = ; i <= n; ++i) {

        sum += i;

    }

    cout << "Sum = " << sum;

    return ;

}

C++ 实例 - 判断闰年

#include <iostream>

using namespace std;

int main()

{

    int year;

    cout << "输入年份: ";

    cin >> year;

    if (year %  == )

    {

        if (year %  == )

        {

            // // 这里如果被 400 整数是闰年

            if (year %  == )

                cout << year << " 是闰年";

            else

                cout << year << " 不是闰年";

        }

        else

            cout << year << " 是闰年";

    }

    else

        cout << year << " 不是闰年";

    return ;

}

C++ 实例 - 求一个数的阶乘

#include <iostream>

using namespace std;

int main()

{

    unsigned int n;

    unsigned long long factorial = ;

    cout << "输入一个整数: ";

    cin >> n;

    for(int i = ; i <=n; ++i)

    {

        factorial *= i;

    }

    cout << n << " 的阶乘为："<< " = " << factorial;

    return ;

}

C++ 实例 - 创建各类三角形图案

#include <iostream>

using namespace std;

int main()

{

    int rows;

    cout << "输入行数: ";

    cin >> rows;

    for(int i = ; i <= rows; ++i)

    {

        for(int j = ; j <= i; ++j)

        {

            cout << "* ";

        }

        cout << "\n";

    }

    return ;

}

#include <iostream>

using namespace std;

int main()

{

    char input, alphabet = 'A';

    cout << "输入最后一个大写字母: ";

    cin >> input;

    for(int i = ; i <= (input-'A'+); ++i)

    {

        for(int j = ; j <= i; ++j)

        {

            cout << alphabet << " ";

        }

        ++alphabet;

        cout << endl;

    }

    return ;

}

#include <iostream>

using namespace std;

int main()

{

    int rows;

    cout << "输入行数: ";

    cin >> rows;

    for(int i = rows; i >= ; --i)

    {

        for(int j = ; j <= i; ++j)

        {

            cout << "* ";

        }

        cout << endl;

    }

    return ;

}

#include <iostream>

using namespace std;

int main()

{

    int rows;

    cout << "输入行数: ";

    cin >> rows;

    for(int i = rows; i >= ; --i)

    {

        for(int j = ; j <= i; ++j)

        {

            cout << j << " ";

        }

        cout << endl;

    }

    return ;

}

#include <iostream>

using namespace std;

int main()

{

    int space, rows;

    cout <<"输入行数: ";

    cin >> rows;

    for(int i = , k = ; i <= rows; ++i, k = )

    {

        for(space = ; space <= rows-i; ++space)

        {

            cout <<"  ";

        }

        while(k != *i-)

        {

            cout << "* ";

            ++k;

        }

        cout << endl;

    }

    return ;

}

#include <iostream>

using namespace std;

int main()

{

    int rows, count = , count1 = , k = ;

    cout << "输入行数: ";

    cin >> rows;

    for(int i = ; i <= rows; ++i)

    {

        for(int space = ; space <= rows-i; ++space)

        {

            cout << "  ";

            ++count;

        }

        while(k != *i-)

        {

            if (count <= rows-)

            {

                cout << i+k << " ";

                ++count;

            }

            else

            {

                ++count1;

                cout << i+k-*count1 << " ";

            }

            ++k;

        }

        count1 = count = k = ;

        cout << endl;

    }

    return ;

}

#include <iostream>

using namespace std;

int main()

{

    int rows;

    cout << "输入行数: ";

    cin >> rows;

    for(int i = rows; i >= ; --i)

    {

        for(int space = ; space < rows-i; ++space)

            cout << "  ";

        for(int j = i; j <= *i-; ++j)

            cout << "* ";

        for(int j = ; j < i-; ++j)

            cout << "* ";

        cout << endl;

    }

    return ;

}

#include <iostream>

using namespace std;

int main()

{

    int rows, coef = ;

    cout << "Enter number of rows: ";

    cin >> rows;

    for(int i = ; i < rows; i++)

    {

        for(int space = ; space <= rows-i; space++)

            cout <<"  ";

        for(int j = ; j <= i; j++)

        {

            if (j ==  || i == )

                coef = ;

            else

                coef = coef*(i-j+)/j;

            cout << coef << "   ";

        }

        cout << endl;

    }

    return ;

}

#include <iostream>

using namespace std;

int main()

{

    int rows, number = ;

    cout << "输入行数: ";

    cin >> rows;

    for(int i = ; i <= rows; i++)

    {

        for(int j = ; j <= i; ++j)

        {

            cout << number << " ";

            ++number;

        }

        cout << endl;

    }

    return ;

}

C++ 实例 - 求两数的最大公约数

#include <iostream>

using namespace std;

int main()

{

    int n1, n2;

    cout << "输入两个整数: ";

    cin >> n1 >> n2;

    while(n1 != n2)

    {

        if(n1 > n2)

            n1 -= n2;

        else

            n2 -= n1;

    }

    cout << "HCF = " << n1;

    return ;

}

C++ 实例 - 求两数最小公倍数

#include <iostream>

using namespace std;

int main()

{

    int n1, n2, max;

    cout << "输入两个数: ";

    cin >> n1 >> n2;

    // 获取最大的数

    max = (n1 > n2) ? n1 : n2;

    do

    {

        if (max % n1 ==  && max % n2 == )

        {

            cout << "LCM = " << max;

            break;

        }

        else

            ++max;

    } while (true);

    return ;

}

C++ 实例 - 实现一个简单的计算器

#include <iostream>

using namespace std;

int main()

{

    char op;

    float num1, num2;

    cout << "输入运算符：+、-、*、/ : ";

    cin >> op;

    cout << "输入两个数: ";

    cin >> num1 >> num2;

    switch(op)

    {

        case '+':

            cout << num1+num2;

            break;

        case '-':

            cout << num1-num2;

            break;

        case '*':

            cout << num1*num2;

            break;

        case '/':

            cout << num1/num2;

            break;

        default:

            // 如果运算符不是 +, -, * 或 /, 提示错误信息

            cout << "Error!  请输入正确运算符。";

            break;

    }

    return ;

}

猴子吃桃问题

一只小猴子一天摘了许多桃子，第一天吃了一半，然后忍不住又吃了一个；第二天又吃了一半，再加上一个；后面每天都是这样吃。到第10天的时候，小猴子发现只有一个桃子了。问小猴子第一天共摘了多少个桃子。

#include <iostream>

using namespace std;

int main()

{

    int x, y, n;

    for (x=, n=; n<; y=(x+)*, x=y, n++);

        cout<<"第一天共摘的桃子数量为 "<<x<<endl;

    return ;

}