C++黑马程序员——P189-192. string容器 构造函数,赋值,拼接,查找和替换
- P189. string容器——构造函数
- P190. ...——赋值操作
- P191. ...——字符串拼接
- P192. ...——字符串查找和替换
- P189. 构造函数
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1 #include <iostream>
2 #include <string>
3
4 using namespace std;
5
6 void test01()
7 {
8 string s1; //默认构造
9
10 const char* str = "hello world";
11 string s2(str); //第二种构造方法
12 cout << "s2 = " << s2 << endl;
13
14 string s3(s2); //拷贝构造
15 cout << "s3 = " << s3 << endl;
16
17 string s4(10, 'a'); //10个a
18 cout << "s4 = " << s4 << endl;
19 }
20
21 int main() {
22 test01();
23 return 0;
24 }
res：
- P190. 赋值操作
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1 void test01()
2 {
3 string str1;
4 str1 = "hello world"; //char*类型字符串 赋值给string类型字符串
5 cout << "str1 = " << str1 << endl;
6
7 string str2;
8 str2 = str1;
9 cout << "str2 = " << str2 << endl;
10
11 string str3;
12 str3 = 'a'; //字符赋值给字符串
13 cout << "str3 = " << str3 << endl;
14
15 string str4;
16 str4.assign("hello C++");
17 cout << "str4 = " << str4 << endl;
18
19 string str5;
20 str5.assign("hello C++", 7); //把字符串的前n个字符赋值给当前字符串
21 cout << "str5 = " << str5 << endl;
22
23 string str6;
24 str6.assign(str5);
25 cout << "str6 = " << str6 << endl;
26
27 string str7;
28 str7.assign(10, 'w'); //n个字符 赋值给字符串
29 cout << "str7 = " << str7 << endl;
30 }
31
32 int main() {
33 test01();
34 return 0;
35 }
res:
总结：‘=’ 和 assign
- P191. 字符串拼接
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1 void test01()
2 {
3 // +=
4 string str1 = "我";
5 str1 += "爱玩游戏"; //+= char*
6 str1 += ':'; //+= 字符
7
8 string str2 = "辐射4";
9 str1 += str2; //+= string字符串
10 cout << str1 << endl;
11
12 // append
13 string str3 = "I";
14 str3.append(" like ");
15 str3.append("game abced", 6); //字符串的前6个字符
16 cout << str3 << endl;
17 str3.append(str2);
18 str3.append(str2, 0, 2); //从第0个位置开始的2个字符(C++中一个汉字占2个字符)
19 cout << str3 << endl;
20 }
21
22 int main() {
23 test01();
24 return 0;
25 }
res：
总结： ‘+=’ 和 append
- P192. 字符串查找和替换
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1 //字符串查找和替换
2 //1. 查找
3 void test01() {
4 string str1 = "abcdefgde";
5 int pos = str1.find("de");
6 cout << pos << endl;
7 pos = str1.find("df");
8 cout << pos << endl;
9 //rfind 和 find 的区别
10 //rfind是从右往左查找，find是从左往右查找 (返回的都是 查找的字符串的 第一个字符的位置)
11 pos = str1.rfind("de");
12 cout << pos << endl;
13 }
14
15 //2. 替换
16 void test02() {
17 string str1 = "abcdefg";
18 str1.replace(1, 3, "1111");
19 cout << str1 << endl;
20 }
21
22 int main() {
23 test01();
24 test02();
25 return 0;
26 }
res：
(〃＞＿＜;〃)(〃＞＿＜;〃)(〃＞＿＜;〃)
