C++之string

embedded/2024/10/18 7:55:35/

1、标准库string类型

2、string对象的定义和初始化

#include <string>
#include <iostream>
using namespace std;int main() {string s1;string s2("abcdefghijklmn");cout << s2 << endl;basic_string<char> s3("xxxx");  // basic_string<char> 等价于string，其实string 就是一个模板，basic_string<char> 是它的原型cout << s3 << endl;string s4("abcdefg", 4);cout << s4 << endl;string s5(s2, 2, 3);cout << s5 << endl;string::iterator first = s2.begin() + 1;string ::iterator last = s2.begin() + 3;string s6(first, last);  // [first, last)cout << s6 << endl;return 0;
}// 输出
abcdefghijklmn
xxxx
abcd
cde
bc

3、常用的成员函数

#include <string>
#include <iostream>
using namespace std;int main() {string s1("abcdefghi");cout << s1.size() << endl;cout << s1.length() << endl;cout << s1.empty() << endl;cout << s1.substr(1, 2) << endl;cout << s1.substr(1) << endl;string::size_type pos = s1.find('d', 1);if(pos == string::npos){cout << "not found" << endl;}else{cout << "pos = " << pos << endl;}pos = s1.rfind('d');if(pos == string::npos){cout << "not found" << endl;}else{cout << "pos = " << pos << endl;}return 0;
}// 输出
9
9
0
bc
bcdefghi
pos = 3
pos = 3

#include <string>
#include <iostream>
using namespace std;int main() {string s1("abcdefghijkl");s1.replace(2, 2, "AAAAA");cout << s1 << endl;s1 = "abcdefg";s1.replace(s1.begin() + 1, s1.begin() + 4, "BBBBB");cout << s1 << endl;string s2 = "xyzabc";s2.insert(2, "FFFFFF");cout << s2 << endl;s2.append("7777777777");cout << s2 << endl;string s3 = "111";s2.swap(s3);cout << s2 << endl;cout << s3 << endl;return 0;
}// 输出
abAAAAAefghijkl
aBBBBBefg
xyFFFFFFzabc
xyFFFFFFzabc7777777777
111
xyFFFFFFzabc7777777777

#include <string>
#include <iostream>
using namespace std;void fun(char* str)
{cout << str << endl;
}
int main() {string s1 = "abc";s1[1] = 'B';cout << s1 << endl;const string s2 = "xyz";//s2[1] = 'Y';  // function 'operator[]' returns a const valuestring s3 = "132" + s1 + "6547";cout << s3 << endl;fun(const_cast<char*>(s3.c_str()));return 0;
}// 输出
aBc
132aBc6547
132aBc6547