{

string str1(5, 'c');//初始化为5个'c'

string str2("Now is the time...");

string str3(str2, 11, 4);//从str2的第11个字符开始，读取4个字符

string str4;

str4.append(3, 'h');//增加3个'h'

char chr[6];

memset(chr, '\0', sizeof(chr));

chr[0] = '2';

string str5(chr);

cout << endl << "InitialDemo:" << endl;

cout << str1 << endl;

if(str1[5]== '\0')

{

cout << "越界输出：str1[5]=\0" << endl;//空

}

else

{

cout << "越界输出：str1[5]=" << str1[5] << endl;//空

}

//cout << "越界输出：str1[6]=" << str1[6] << endl;//异常

cout << str2 << endl;

cout << str3 << endl;

cout << str4 << endl;

cout << str5 << endl;

{

cout << endl << "AssignReplaceDemo:" << endl;

string str1, str2 = "War and Peace";

str1.assign(str2, 4, 3);

//结果为and

cout << str1 << endl;

string s = "They say he carved it himself...from a BIGGER spoon";

string s2 = "find your soul-mate, Homer.";

//s[1] = "1";不能用这种形式

//replace(off,number,new string)

//结果为They find your soul-mate, Homer.from a BIGGER spoon

s.replace(5, s2.length(), s2);

cout << s << endl;

{

int left = 0, right = s.size() - 1;

while (left < right)

{

char t = s[left];

s[left++] = s[right];

s[right--] = t;

}

return s;

int left = 0, right = s.size() - 1;

while (left < right) {

swap(s[left++], s[right--]);

}

return s;

{

cout << endl << "Change2CharDemo:" << endl;

string str1 = "War and Peace";

const char* chr = str1.c_str();

cout << chr << endl;

//定义成char chr2[10]是一样的

char* chr2 = "to_string";

string str2 = chr2;

cout << str2 << endl;

{

cout << endl << "Change2IntDemo" << endl;

//stoi：string转int

string str1 = "-20";

string str2 = "5";

int ret = stoi(str1) + stoi(str2);

cout << "string to int: -20+5=" << ret << " " << endl;

//to_string：数值转string

int a = -3, b = 37;

string a_plus_b = to_string(a + b);

cout << "int to string: -3+37=" << a_plus_b << " " << endl;

//strtol：string转long。_Radix表示进制。

//stol：string转long，并做进制转换。Base=0时使用默认的十进制

string str3 = "-0x12";

string str4 = "0x76E";//1902

char *offset;

cout << "string to int: -0x12=" << strtol(str3.c_str(),&offset,0) << " " << endl;

cout << "string to int: 0x76E=" << strtol(str4.c_str(), &offset, 0) << " " << endl;

cout << "string to int: 0x76E=" << stol(str4, nullptr,0) << " " << endl;

string str5 = "A4";

char *offset5;

int istr5 = strtol(str5.c_str(), &offset5, 10);

cout << "string to int: A4=" << istr5 << " " << endl;//0

{

string str = "20+-22i";

int size = str.size();

int plus = str.find("+");

string real = str.substr(0, plus);//off,count

string imaginary = str.substr(plus + 1, size - plus - 2);

cout << "substring: " << real << " " << imaginary << endl;

{

string str;

cout << "FindDemo: please cin words and find spaces "<<endl;

getline(cin, str);

//hello world=5

//helloworld=-1=string

int begin = str.find(' ');

int end = str.find_last_of(' ');//hello world =5

string last(str, end + 1, str.size() - end);

cout << last<<" "<<last.size() << endl;;

{

cout << endl << "AddDemo" << endl;

string str = "";

str += "5";

cout << str << endl;

str.append("11");

cout << str << endl;

str.append(5,'0');

cout << str << endl;

{

cout << endl << "CompareDemo:" << endl;

string str1("aaa");

string str2("aab");

string str3("aaaa");

bool ret = str1 < str2;

cout << ret << endl;

ret = str1 < str3;

cout << ret << endl;

ret = str2 < str3;

cout << ret << endl;

{

wstring wstr1;

wstr1 = L"我ABC的string";

wstring wstr2(L"我A的XX啊");

int s1 = wstr1.size();

cout << endl << "begin SplitDemo" << endl;

string str = "hello world! this is a string.";

vector<string> str_arr;

string temp;

int offset = 0;

int newOffset = 0;

//获取空格位置，没有空格时返回-1

while (offset<str.size()&& newOffset>=0)

{

newOffset = str.find(' ', offset);

temp = str.substr(offset, newOffset - offset);

str_arr.push_back(temp);

offset = newOffset + 1;

}

cout << "origin string = " << str << endl;

cout << "split arr size = " << str_arr.size() << endl;

for (int i = 0;i < str_arr.size();i++) {

cout << "str_arr[" << i << "] = " << str_arr[i] << endl;

}

cout << "end SplitDemo" << endl;

{

SplitDemo();

WStringDemo();

InitialDemo();

AssignReplaceDemo();

Change2CharDemo();

Change2IntDemo();

SubStringDemo();

FindDemo();

AddDemo();

CompareDemo();

system("pause");

return 0;