字符串的综合操作 C++ Builder示例

#include <iostream> #include <string> //string类头文件 using namespace std; #include "UnicodeToANSI.h" #include <vcl.h> #pragma hdrstop #include "Unit1.h" // --------------------------------------------------------------------------- #pragma package(smart_init) #pragma resource "*.dfm" TForm1 *Form1; // --------------------------------------------------------------------------- __fastcall TForm1::TForm1(TComponent* Owner) : TForm(Owner) { } // ---------字符串迭代器与反向迭代器------------------------------------------ void __fastcall TForm1::Button1Click(TObject *Sender) { Memo1->Text = "字符串迭代器与反向迭代器 C++ Builder窗口示例"; string line("One,Two,Three"); string s(line.begin(), line.end()); // 正向遍历容器 UnicodeString su = ANSIToUnicode(s); Memo1->Lines->Add("正向遍历:" + su); string s2(line.rbegin(), line.rend()); // 反向遍历容器 su = ANSIToUnicode(s2); Memo1->Lines->Add("反向遍历:" + su); // -------------------------------------------- int i = 0; char arr[255]; string::iterator itr; // 定义迭代器 for (itr = line.begin(); itr != line.end(); itr++) { arr[i] = *itr; i++; } string s3; for (i = 0; i < line.length(); i++) { s3 = s3 + arr[i]; } su = ANSIToUnicode(s3); Memo1->Lines->Add("正向迭代:" + su); // -------------------------------------------- i = 0; for (itr = line.end() - 1; itr != line.begin(); itr--) { arr[i] = *itr; i++; } s3 = ""; for (i = 0; i < line.length(); i++) { s3 = s3 + arr[i]; } su = ANSIToUnicode(s3); Memo1->Lines->Add("反向迭代:" + su); // -------------------------------------------- string::reverse_iterator ritr; // 定义反向迭代器 i = 0; for (ritr = line.rbegin(); ritr != line.rend(); ritr++) { arr[i] = *ritr; i++; } s3 = ""; for (i = 0; i < line.length(); i++) { s3 = s3 + arr[i]; } su = ANSIToUnicode(s3); Memo1->Lines->Add("定义反向迭代:" + su); } // --------------------------------------------------------------------------- void __fastcall TForm1::Button2Click(TObject *Sender) { Memo1->Text = "字符串容量 C++ Builder窗口示例"; string str("0123456789"); str.reserve(12); // 重新分配空间，保留字符数 Memo1->Lines->Add("str=" + ANSIToUnicode(str)); str.resize(8); // 修改字符串：多去少补('a') Memo1->Lines->Add("str=" + ANSIToUnicode(str)); int size = str.size(); int length = str.length(); int capacity = str.capacity(); // 初值15，每次+16 // capacity: 与resize和reserve都有关 unsigned long maxsize = str.max_size(); // __int64, 2^32=4294967296(4) Memo1->Lines->Add("size=" + IntToStr(size)); Memo1->Lines->Add("length=" + IntToStr(length)); Memo1->Lines->Add("capacity=" + IntToStr(capacity)); Memo1->Lines->Add("maxsize=" + (UnicodeString)(maxsize)); if (!str.empty()) str.clear(); // 判空与清空 Memo1->Lines->Add("str=" + ANSIToUnicode(str)); } // --------------------------------------------------------------------------- void __fastcall TForm1::Button3Click(TObject *Sender) { Memo1->Text = "修改字符串_赋值 C++ Builder窗口示例"; string s1("012345abcdef"); string s2; s2.assign(s1); Memo1->Lines->Add("s2=" + ANSIToUnicode(s2)); s2.assign(s1, 6, 3); Memo1->Lines->Add("s2=" + ANSIToUnicode(s2)); s2.assign(s1, 2, s1.npos); // npos表示size_t的最大值 Memo1->Lines->Add("s2=" + ANSIToUnicode(s2)); s2.assign(5, 'X'); // 填充5个X Memo1->Lines->Add("s2=" + ANSIToUnicode(s2)); string::iterator itB = s1.begin(); // 迭代器 string::iterator itE = s1.end(); s2.assign(itB, itE); Memo1->Lines->Add("s2=" + ANSIToUnicode(s2)); s2.assign(itB, itE - 2); Memo1->Lines->Add("s2=" + ANSIToUnicode(s2)); } // --------------------------------------------------------------------------- void __fastcall TForm1::Button4Click(TObject *Sender) { Memo1->Text = "修改字符串_追加 C++ Builder窗口示例"; string s1("123456"); string s2 = "abcdef"; s1.append(s2); Memo1->Lines->Add("s1=" + ANSIToUnicode(s1)); s1.append(s2, 2, 3); Memo1->Lines->Add("s1=" + ANSIToUnicode(s1)); s1.append("ABCDE", 2); Memo1->Lines->Add("s1=" + ANSIToUnicode(s1)); s1.append("ABCDE", 0, 3); Memo1->Lines->Add("s1=" + ANSIToUnicode(s1)); s1.append(3, 'X'); Memo1->Lines->Add("s1=" + ANSIToUnicode(s1)); // ---------追加单个字符---------------------- s1.append(1, 'Y'); Memo1->Lines->Add("s1=" + ANSIToUnicode(s1)); s1.push_back('Z'); Memo1->Lines->Add("s1=" + ANSIToUnicode(s1)); s1 += "W"; Memo1->Lines->Add("s1=" + ANSIToUnicode(s1)); } // --------------------------------------------------------------------------- void __fastcall TForm1::Button5Click(TObject *Sender) { Memo1->Text = "修改字符串_插入与删除 C++ Builder窗口示例"; string s1("0123456789"); string s2 = "abcd"; Memo1->Lines->Add("s1=" + ANSIToUnicode(s1)); s1.erase(7); Memo1->Lines->Add("s1=" + ANSIToUnicode(s1)); s1.erase(3, 2); Memo1->Lines->Add("s1=" + ANSIToUnicode(s1)); s2.insert(2, s1); Memo1->Lines->Add("s2=" + ANSIToUnicode(s2)); s2.insert(0, "ABC"); Memo1->Lines->Add("s2=" + ANSIToUnicode(s2)); s2.insert(3, "幸运骄子"); Memo1->Lines->Add("s2=" + ANSIToUnicode(s2)); Memo1->Lines->Add("s2_size:" + (UnicodeString)(s2.size())); cout << s2.insert(4, "Y") << endl; Memo1->Lines->Add("s2=" + ANSIToUnicode(s2) + "<--乱码"); cout << s2.erase(4, 1) << endl; Memo1->Lines->Add("s2=" + ANSIToUnicode(s2)); cout << s2.insert(5, "Y") << endl; Memo1->Lines->Add("s2=" + ANSIToUnicode(s2)); } // --------------------------------------------------------------------------- void __fastcall TForm1::Button6Click(TObject *Sender) { Memo1->Text = "修改字符串_替换与交换 C++ Builder窗口示例"; string s1("0123456"); string s2 = "abcdef"; Memo1->Lines->Add("s1=" + ANSIToUnicode(s1)); s1.replace(2, 3, s2); Memo1->Lines->Add("s1=" + ANSIToUnicode(s1)); s1.replace(2, 6, s2, 2, 3); Memo1->Lines->Add("s1=" + ANSIToUnicode(s1)); s1.replace(0, 5, s1, 1, 3); Memo1->Lines->Add("s1=" + ANSIToUnicode(s1)); s1.replace(1, 2, 5, 'X'); Memo1->Lines->Add("s1=" + ANSIToUnicode(s1)); string::iterator itB = s1.begin(); string::iterator itE = s1.end(); s1.replace(itB + 1, itE - 4, s2); Memo1->Lines->Add("s1=" + ANSIToUnicode(s1)); s1.swap(s2); Memo1->Lines->Add("s2=" + ANSIToUnicode(s2)); Memo1->Lines->Add("s1=" + ANSIToUnicode(s1)); } // --------------------------------------------------------------------------- void __fastcall TForm1::Button7Click(TObject *Sender) { Memo1->Text = "字符串操作_C_string C++ Builder窗口示例"; string s("abcdefghij"); // 原string字符串 Memo1->Lines->Add("s:" + ANSIToUnicode(s)); Memo1->Lines->Add("s.length():" + UnicodeString(s.length())); // data() 操作 const char* d = s.data(); // 去掉const 语法错 cout << "d: " << d << endl; Memo1->Lines->Add("d:" + ANSIToUnicode(d)); Memo1->Lines->Add("strlen(d):" + UnicodeString(strlen(d))); // c_str() 操作 const char* cs = s.c_str(); // 去掉const 语法错 Memo1->Lines->Add("cs:" + ANSIToUnicode(cs)); Memo1->Lines->Add("cs[0]:" + UnicodeString(cs[0])); // cs[0]='b'; //尝试修改数组元素会导致错误 Memo1->Lines->Add("strlen(cs):" + UnicodeString(strlen(cs))); char buffer[20]; s.copy(buffer, 10); buffer[0] = 'b'; // 允许修改数组元素 Memo1->Lines->Add("strlen(buffer):" + UnicodeString(strlen(buffer))); string s2 = ""; for (int i = 0; i < 10; i++) { s2 += buffer[i]; } Memo1->Lines->Add("buffer:" + ANSIToUnicode(s2)); } // --------------------------------------------------------------------------- void __fastcall TForm1::Button8Click(TObject *Sender) { Memo1->Text = "字符串操作查找_find() C++ Builder窗口示例"; // 查找单个字符 string str1("Hello Everyone"); Memo1->Lines->Add("str1:" + ANSIToUnicode(str1)); int index; // index的类型： basic_string <char>::size_type; index = str1.find('e', 2); // str1[2]开始找，缺省为0 if (index != string::npos) // npos=-1 串尾 Memo1->Lines->Add("e:" + IntToStr(index)); 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