量化交易之C++篇 - string 容器

#include <iostream>
#include <string>
#include <cstring>

using namespace std;

void test01() {

  string string1; // 默认构造
  string string2(string1); // copy构造
  string string3 = string1;

  string string4 = "abcd";
  string string5(10, 'a');


  // 基本赋值
  string1 = "hello";
  string2 = string4;

  string3.assign("abcdef", 4);

  string string6;
  string6.assign(string1, 1, 3);

  cout << string6 << endl;
}


void test02() {

  string string1 = "hello world";

  for (int i = 0; i < string1.size(); i++) {
    //cout << string1[i] << endl;
    cout << string1.at(i) << endl; // [] 和 at 的区别: 当访问越界时, []直接挂掉, at会抛出异常;
  }

  try {
    string1.at(100);
  }
  catch(out_of_range &exception) {
    cout << "out_of_range: " << exception.what() << endl;
  }
  catch(...) {
    cout << "unknown error" << endl;
  }
}

void test03() {
  // 字符串拼接
  string string1 = "I";
  string string2 = (string1 += " love xuyushan");

  cout << string2 << endl;
  string2.append(" forever");
  cout << string2 << endl;
}

void test04() {

  // find 查找
  string string1 = "abcdefg";
  int position1 = string1.find("bcd"); // 从左开始找: 如果没有找到则返回 -1
  cout << "position1 = " << position1 << endl;

  int position2 = string1.rfind("bc");
  cout << "position2 = " << position2 << endl; // 从右开始找: 如果没有找到则返回 -1
}

void test05() {
  // replace 替换

  string string2 = "hello";
  string2.replace(1, 3, "111");
  cout << string2 << endl;
}

void test06() {

  string string1 = "abc";
  string string2 = "abc";

  if (string1.compare(string2) == 0) {
    cout << "string1 == string2" << endl;
  } else if (string1.compare(string2) == 1) {
    cout << "string1 > string2" << endl;
  } else if (string1.compare(string2) == -1) {
    cout << "string1 < string2" << endl;
  }
}


void test07() {
  // 子串
  string string1 = "abcde";

  string string2 = string1.substr(1, 3);
  //cout << string2 << endl;

  string email = "[e-mail]";
  int position = email.find("@");
  cout << email.substr(0, position) << endl;
}

void test08() {

  // 插入 删除
  string string1 = "hello";
  string1.insert(1, "111"); // 插入
  cout << string1 << endl;

  string1.erase(1, 3); // 删除
  cout << string1 << endl;
}


void stringFunction(string someString) {

  cout << someString << endl;
}

void test09() {

  string string1 = "abc";

  const char* p = string1.c_str();

  stringFunction(p); // 隐式类型转换为 string
  
}


string& tocapitalize(string& tempString) {
  for (int i = 0; i < tempString.size(); i++) {

    if (i == 0) {
      tempString[i] = toupper(tempString[i]);
      continue;
    }
    tempString[i] = tolower(tempString[i]);
  }

  return tempString;
}

// 自定义字符串操作函数
void test10() {

  string string1 = "abCdEfg";

  tocapitalize(string1);

  cout << string1 << endl;

}

int main() {

  //test01();

  //test02();

  //test03();

  //test04();

  //test05();

  //test06();

  //test07();

  //test08();

  //test09();

  test10();

  return EXIT_SUCCESS;
}