练习~黑马程序员匠心之作-第一阶段C++基础入门-P16~P23-简单计算

黑马程序员匠心之作|C++教程从0到1入门编程

关于P16~P18练习

1、基本知识：加减乘除，取模，递增递减

#include <iostream>
using namespace std;

int main() {

	//1、前置递增
	int a = 10;
	++a;//让变量+1
	cout <<"a=" <<a << endl;

    //2、后置递增
	int b = 10;
	b++;//让变量+1
	cout << "b=" << b << endl;

	//3、前置与后置区别
	//前置递增，先让变量+1，然后进行表达式运算
	int a2 = 10;
	int b2 = ++a2 * 10;
	cout << "a2=" << a2 << endl; //11
	cout << "b2="<<b2 <<endl; //110,先+1后×10

	//后置递增，先进行表达式运算，然后让变量+1
	int a3 = 10;
	int b3 = a3++ * 10;
	cout << "a3=" << a3 << endl; //11
	cout << "b3=" << b3 << endl; //100，先a3×10，后a3+1

	//加减乘除
	int a1 = 10;
	int b1 = 3;
	cout << a1 + b1 << endl;
	cout << a1 - b1 << endl;
	cout << a1 * b1 << endl;
	cout << a1 / b1 << endl; //两个整数相除，结果为整数，小数部分去除，3
	cout << a1% b1 << endl;  //取模运算本质就是求余数，1

	int a2 = 10;
	int b2 = 20;
	cout << a2 / b2 << endl; //0
	cout << a2 % b2 << endl; //结果为10，

	int a3 = 10;
	int b3 = 0;
	//cout << a3 / b3 << endl; //非法操作，两数相除，除数不为零
	//cout << a3 % b3 << endl; //非法操作，两数相除，除数不为零，所以做不了取模运算

	//两个小数相除，不可以取模运算
	double d1 = 0.5;
	double d2 = 0.22;
	cout << d1 / d2 << endl;//运算结果可以是小数

	system("pause");
	return 0;
}
           

关于P19~P20练习

1、基本知识：

赋值运算符：=，+=，-=，*=，/=，%=；

比较运算符：==，！=，>，<，>=，<=；

//赋值运算
	// =
	int a = 10;
	a = 100;
	cout << "a=" << a << endl;

	// +=
    a = 10;
	a += 2; //a=a+2
	cout << "a=" << a << endl; //12

	// -=
	a = 10;
	a -= 2; //a=a+2
	cout << "a=" << a << endl; //8

	// *=
	a = 10;
	a *= 2; 
	cout << "a=" << a << endl; //20

	// /=
	a = 10;
	a /= 2; 
	cout << "a=" << a << endl;  //5

	// %=
	a = 10;
	a %= 2; 
	cout << "a=" << a << endl; //0

//比较运算符
	// ==
	int a = 10;
	int b = 20;
	cout << (a == b) << endl; //0
	// !=
	cout << (a != b) << endl; //1
	// >
	cout << (a > b) << endl; //0
	// <
	cout << (a < b) << endl; //1
	// >=
	cout << (a >= b) << endl; //0
	// <=
	cout << (a <= b) << endl; //1
	
           

关于P21~P23练习

1、基本知识：

逻辑运算符：非！，与&&，或||

//逻辑运算符

	//非！
	int a = 10;
	//在C++中，除了0，皆为真
	cout << !a << endl; //真变假，假变真,0
	cout << !!a << endl; //1

	//与&&,同真为真，其余为假
	 a = 10;
	int b = 10;
	cout << (a && b) << endl;//1

	 a = 0;
	 b = 10;
	cout << (a && b) << endl;//0

	 a = 0;
	 b = 0;
	cout << (a && b) << endl;//0

	//或||，同假为假，其余为真
	a = 10;
	b = 10;
	cout << (a || b) << endl;//1

	a = 0;
	b = 10;
	cout << (a || b) << endl;//1

	a = 10;
	b = 0;
	cout << (a || b) << endl;//1

	a = 0;
	b = 0;
	cout << (a || b) << endl;//0