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简单的 C++ 数学运算

了解 C++ 中使用的算术运算符。

检查点

简单的 C++ 数学运算

了解 C++ 中使用的算术运算符。

符号算术运算
+加法
-减法
/除法
*乘法
%取余（或模运算）
1#include <iostream>
2using namespace std;
3
4int main() {
5    cout << 15 + 5 << endl; // 加法
6    cout << 15 - 5 << endl; // 减法
7    cout << 15 * 5 << endl; // 乘法
8    cout << 15 / 5 << endl; // 除法
9    cout << 15 % 5 << endl; // 取余
10    return 0; 
11}
1#include <iostream>
2using namespace std;
3
4int main() {
5  int num1, num2, res;
6  num1 = 15;
7  num2 = 5;
8  res = 0;
9  res = num1 + num2;  // 加法
10  cout << res << endl;
11  res = num1 - num2;  // 减法
12  cout << res << endl;
13  res = num1 * num2;  // 乘法
14  cout << res << endl;
15  res = num1 / num2;  // 除法
16  cout << res << endl;
17  res = num1 % num2;  // 取余
18  cout << res << endl;
19  return 0;
20}
1#include <iostream>
2using namespace std;
3
4int main() {
5  cout << 15 / 4 << endl;
6	cout << 15.0 / 4.0 << endl;
7  cout << 15.0 / 4 << endl;
8	cout << 15 / 4.0 << endl;
9  return 0;
10}
1#include <iostream>
2using namespace std;
3
4int main() {
5  // 抵消误差（Cancellation Error）
6  cout << 1100.0 + 0.00000000000008 << endl;
7  // 算术溢出（Arithmetic Overflow）
8  // cout << 9999999999999999999999 + 8989898989898989898 << endl;
9  return 0;
10}

代码示例

1x + y - z
1.

What is the result of the following operation?

112 / 3 * 2
0/500
1#include <iostream>
2using namespace std;
3
4int main() {
5  // 20 + 30 * 2 / 10 - 3
6  cout << "答案是 " <<  20 + 30 * 2 / 10 - 3 << endl;
7  return 0;
8}

代码示例

1a = a + b;

代码示例

1a += b;

表格

符号运算
+=加法赋值
-=减法赋值
*=乘法赋值
/=除法赋值
%=取余赋值
1#include <iostream>
2using namespace std;
3
4int main() {
5  int a, b;
6  a = 9;
7  b = 3;
8  cout << "a:" << a <<endl; // a = 9
9  cout << "b:" << b << endl; // b = 3
10  a += b;
11  cout << "a += b" << endl;
12  cout << "a:" << a <<endl; // a = 12
13  cout << "b:" << b << endl; // b = 3
14  a -= b;
15  cout << "a -= b" << endl;
16  cout << "a:" << a <<endl; // a = 9
17  cout << "b:" << b << endl; // b = 3
18  a *= b;
19  cout << "a *= b" << endl;
20  cout << "a:" << a <<endl; // a = 27
21  cout << "b:" << b << endl; // b = 3
22  a /= b;
23  cout << "a /= b" << endl;
24  cout << "a:" << a <<endl; // a = 9
25  cout << "b:" << b << endl; // b = 3
26  a %= b;
27  cout << "a %= b" << endl;
28  cout << "a:" << a <<endl; // a = 0
29  cout << "b:" << b << endl; // b = 3
30  return 0;
31}
1#include <iostream>
2using namespace std;
3
4int main() {
5  int val = 0;
6  
7  // 后置递增
8  cout << val << endl;
9  cout << val++ << endl;
10  cout << val++ << endl;
11
12  // 后置递减  
13  cout << val << endl;
14  cout << val-- << endl;
15  cout << val-- << endl;
16  
17  // 最终值
18  cout << val << endl;
19
20  return 0;
21}
1#include <iostream>
2using namespace std;
3
4int main() {
5  int val = 0;
6  
7  // 前置递减
8  cout << val << endl;
9  cout << --val << endl;
10  cout << val << endl;
11
12  // 前置递增  
13  cout << val << endl;
14  cout << ++val << endl;
15  cout << val << endl;
16  
17  return 0;
18}
1.

What is the output of the following code?

1int x = 5;
2cout << x++ << " ";
3cout << ++x << endl;
0/500

Quiz

单选题

以下表达式的输出结果是什么？

12 + 15 * ( 7 + (2 * 0) )
1 / 2

指针与数组

类型转换