support bazel complie this project and format code.

practical_exercises/10_day_practice/day7/binary_operator/BUILD

@@ -0,0 +1,13 @@
+# please run `bazel run //practical_exercises/10_day_practice/day7/binary_operator:operator`
+# please run `bazel run //practical_exercises/10_day_practice/day7/binary_operator:friend_operator`
+
+load("@rules_cc//cc:defs.bzl", "cc_binary")
+
+cc_binary(
+    name = "operator",
+    srcs = ["operator.cpp"],
+)
+cc_binary(
+    name = "friend_operator",
+    srcs = ["friend_operator.cpp"],
+)

practical_exercises/10_day_practice/day7/binary_operator/friend_operator.cpp

@@ -0,0 +1,85 @@
+/* 2.友元运算符实现.cpp */
+
+/*
+在C++的标准命名空间std中预定义了复数类Complex，
+并且通过友元重载了Complex的各种运算，包括本程序中重载的+、-、*、/。
+若使用using namespace std将std名字空间引入本程序，
+则本程序中的Complex将与std名字空间中的Complex类的运算符重载函数产生冲突，引起编译错误。
+*/
+/*
+对于不要求左值且可以交换参数次序的运算符（如+、-、*、/ 等运算符），
+最好用非成员形式（包括友元和普通函数）的重载运算符函数实现。
+*/
+
+//解决前面的2+b问题。
+#include <iostream>
+
+class Complex {
+private:
+  double r, i;
+
+public:
+  Complex(double R = 0, double I = 0) : r(R), i(I){};
+  friend Complex operator+(Complex a, Complex b);
+  friend Complex operator-(Complex a, Complex b);
+  friend Complex operator*(Complex a, Complex b);
+  friend Complex operator/(Complex a, Complex b);
+
+  friend Complex operator+(Complex a, double b) {
+    return Complex(a.r + b, a.i);
+  }
+  friend Complex operator+(double a, Complex b) {
+    return Complex(a + b.r, b.i);
+  }
+
+  void display();
+};
+
+Complex operator+(Complex a, Complex b) {
+  return Complex(a.r + b.r, a.i + b.i);
+}
+Complex operator-(Complex a, Complex b) {
+  return Complex(a.r - b.r, a.i - b.i);
+}
+Complex operator*(Complex a, Complex b) {
+  Complex t;
+  t.r = a.r * b.r - a.i * b.i;
+  t.i = a.r * b.i + a.i * b.r;
+  return t;
+}
+Complex operator/(Complex a, Complex b) {
+  Complex t;
+  double x;
+  x = 1 / (b.r * b.r + b.i * b.i);
+  t.r = x * (a.r * b.r + a.i * b.i);
+  t.i = x * (a.i * b.r - a.r * b.i);
+  return t;
+}
+
+void Complex::display() {
+  std::cout << r;
+  if (i > 0)
+    std::cout << "+";
+  if (i != 0)
+    std::cout << i << "i" << std::endl;
+}
+int main(void) {
+  Complex c1(1, 2), c2(3, 4), c3, c4, c5, c6;
+  Complex a, b(2, 3);
+  Complex a1 = b + 2;
+  Complex a2 = 2 + b;
+  a1.display();
+  a2.display();
+  c3 = c1 + c2;
+  c4 = c1 - c2;
+  c5 = c1 * c2;
+  c6 = c1 / c2;
+  c1.display();
+  c2.display();
+  c3.display();
+  c4.display();
+  c5.display();
+  c6.display();
+  
+  return 0;
+}

practical_exercises/10_day_practice/day7/binary_operator/operator.cpp

@@ -0,0 +1,63 @@
+/* 1.类运算符重载.cpp */
+//有复数类Complex，利用运算符重载实现复数的加、减、乘、除等复数运算。
+#include <iostream>
+using namespace std;
+class Complex {
+private:
+  double r, i;
+
+public:
+  Complex(double R = 0, double I = 0) : r(R), i(I){};
+  Complex operator+(Complex b);
+  Complex operator-(Complex b);
+  Complex operator*(Complex b);
+  Complex operator/(Complex b);
+  void display();
+};
+
+Complex Complex::operator+(Complex b) { return Complex(r + b.r, i + b.i); }
+Complex Complex::operator-(Complex b) { return Complex(r - b.r, i - b.i); }
+//求复数相乘的算法
+Complex Complex::operator*(Complex b) {
+  Complex t;
+  t.r = r * b.r - i * b.i;
+  t.i = r * b.i + i * b.r;
+  return t;
+}
+//求复数相除的算法
+Complex Complex::operator/(Complex b) {
+  Complex t;
+  double x;
+  x = 1 / (b.r * b.r + b.i * b.i);
+  t.r = x * (r * b.r + i * b.i);
+  t.i = x * (i * b.r - r * b.i);
+  return t;
+}
+void Complex::display() {
+  cout << r;
+  if (i > 0)
+    cout << "+";
+  if (i != 0)
+    cout << i << "i" << endl;
+  //}display();
+};
+
+int main(void) {
+  Complex c1(1, 2), c2(3, 4), c3, c4, c5, c6;
+  Complex a, b(2, 3);
+  a = b + 2; //正确
+  // a=2+b;       			//错误
+  a.display();
+  c3 = c1 + c2;
+  c4 = c1 - c2;
+  c5 = c1 * c2;
+  c6 = c1 / c2;
+  c1.display();
+  c2.display();
+  c3.display();
+  c4.display();
+  c5.display();
+  c6.display();
+  
+  return 0;
+}