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运算符
作用：用于执行代码的运算
| 运算符类型 | 作用 | | 算术运算符 | 用于处理四则运算 | | 赋值运算符 | 用于将表达式的值赋给变量 | | 比较运算符 | 用于表达式的比较，并返回一个真值或假值 | | 逻辑运算符 | 用于根据表达式的值返回真值或假值 |
01 算术运算符
| 运算符 | 术语 | 示例 | 结果 | | + | 正号 | +3 | 3 | | - | 负号 | -3 | -3 | | + | 加 | 10+5 | 15 | | - | 减 | 10-5 | 5 | | * | 乘 | 10*5 | 50 | | / | 除 | 10/5 | 2 | | % | 取模/取余 | 10%3 | 1 | | ++ | 前置递增 | a=2;b=++a; | a=3;b=3; | | ++ | 后置递增 | a=2;b=a++; | a=3;b=2; | | -- | 前置递减 | a=2;b=--a; | a=1;b=1; | | -- | 后置递增 | a=2;b=a--; | a=1;b=2; |
#include<iostream>
using namespace std;
int main1()
{
//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，结果依然是整数，将小数部分去除
int a2 = 10;
int b2 = 20;
cout << a2 / b2 << endl;
int a3 = 10;
int b3 = 0;
//cout << a3 / b3 << endl; //错误，除数不可以为0
double x1 = 0.5;
double x2 = 0.22;
cout << x1 / x2 << endl;
//取模
int c1 = 10;
int d1 = 3;
cout << c1 % d1 << endl;
int c2 = 10;
int d2 = 20;
cout << c2 % d2 << endl;
int c3 = 10;
int d3 = 0;
//cout << c3 % d3 << endl; //错误，取模除数不可以为0
double x3 = 3.14;
double x4 = 1.1;
//cout << x3 % x4 << endl; //错误，不支持小数取模运算
//1.前置递增
int m = 10;
++m;
cout << "m = " << m << endl;
//2.后置递增
int n = 10;
n++;
cout << "n = " << n << endl;
//3.前置和后置的区别
//前置递增：先让变量+1，后进行表达式运算
int m2 = 10;
int n2 = ++m2 * 10;
cout << "m2 = " << m2 << endl;
cout << "n2 = " << n2 << endl;
//后置递增：先进行表达式运算，后让变量+1
int m3 = 10;
int n3 = m3++ * 10;
cout << "m3 = " << m3 << endl;
cout << "n3 = " << n3 << endl;
system("pause");
return 0;
}
02 赋值运算符
| 运算符 | 术语 | 示例 | 结果 | | = | 赋值 | a=2;b=3; | a=2;b=3; | | += | 加等于 | a=0;a+=2; | a=2; | | -= | 减等于 | a=5;a-=3; | a=2; | | *= | 乘等于 | a=2;a*=2; | a=4; | | /= | 除等于 | a=4;a/=2; | a=2; | | %= | 模等于 | a=3;a%=2; | a=1; |
#include<iostream>
using namespace std;
int main2()
{
//赋值运算符
int a = 10;
cout << "a = " << a << endl; //10
// +=
a += 2;
cout << "a = " << a << endl; //12
// -=
a = 10;
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
system("pause");
return 0;
}
03 比较运算符
| 运算符 | 术语 | 示例 | 结果 | | == | 相等于 | 4==3 | 0 | | != | 不等于 | 4!=3 | 1 | | < | 小于 | 4<3 | 0 | | > | 大于 | 4>3 | 1 | | <= | 小于等于 | 4<=3 | 0 | | >= | 大于等于 | 4>=3 | 1 |
#include<iostream>
using namespace std;
int main3()
{
//比较运算符
// ==
int a = 10;
int b = 20;
cout << (a == b) << endl;
// !=
cout << (a != b) << endl;
// >
cout << (a > b) << endl;
// <
cout << (a < b) << endl;
// >=
cout << (a >= b) << endl;
// <=
cout << (a <= b) << endl;
system("pause");
return 0;
}
04 逻辑运算符
| 运算符 | 术语 | 示例 | 结果 | | ! | 非 | !a | 如果a为假，则!a为真；如果a为真，则!a为假。 | | && | 与 | a&&b | 如果a和b都为真，则结果为真，否则为假。 | | || | 或 | a||b | 如果a或b有一个为真，则结果为真；二者都为假时，结果为假。 |
#include<iostream>
using namespace std;
int main4()
{
//逻辑运算符 非 !
int a = 10;
cout << !a << endl; //0
cout << !!a << endl; //1
//逻辑运算符 与 &&
int c = 10;
int d = 10;
cout << (c && d) << endl; // 1
c = 0;
d = 10;
cout << (c && d) << endl; // 0
c = 10;
d = 0;
cout << (c && d) << endl; // 0
c = 0;
d = 0;
cout << (c && d) << endl; // 0
//逻辑运算符 或 ||
int e = 10;
int f = 10;
cout << (e || f) << endl; // 1
e = 0;
f = 10;
cout << (e || f) << endl; // 1
e = 10;
f = 0;
cout << (e || f) << endl; // 1
e = 0;
f = 0;
cout << (e || f) << endl; // 0
system("pause");
return 0;
}
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