字符串

 1 #include <iostream>
 2 #include <fstream>
 3 #include <string>
 4 #include <string.h>
 5 using namespace std;
 6 
 7 int main()
 8 {
 9     string s(4,‘x‘);
10     cout << s << endl;//xxxx
11 
12     s += "xx";
13 
14     string buffer = "E:\\1.txt";
15     ifstream infile;
16     infile.open(buffer.c_str());//返回
17 
18     //erase
19     string s1 = "This is a test string";
20     s1.erase(10, 5);
21     cout << s1 << endl;//This is a string
22 
23     //Insert
24     string s2 = "test ";
25     s1.insert(10, s2);
26     cout << s1 << endl;//This is a test string
27 
28     //replace
29     s1 = "This is a string";
30     s1.replace(10, 6, s2);
31     cout << s1 << endl;//This is a test
32 
33     //swap
34     s1.swap(s2);
35     cout << s1 << endl; // test
36 
37     s2[2] = ‘a‘; s2[3] = ‘t‘;
38     cout << s2 << endl;//That is a test
39 
40     //substr
41     s1 = s2.substr(10, 4);
42     cout << s1 << endl;//test
43 
44     //find(子串,初始查找位置）
45     cout << s2.find("is", 0) << endl;//5
46     cout << s2.find("at", 0) << endl;//2
47 
48     //rfind(子串,初始查找位置)从后往前找
49     cout << s2.rfind("a", 13) << endl;//8
50     cout << s2.rfind("t", 13) << endl;//13
51 
52     //find_first_of,find_first_not_of
53     //find_last_of,find_last_not_of
54     s1 = "abcdef";
55     cout << s1.find_first_of("xeyz") << endl;//4
56     cout << s1.find_first_not_of("xyba") << endl;//2
57     cout << s1.find_last_of("xeyz") << endl;//4
58     cout << s1.find_last_not_of("xyba") << endl;//5
59 
60     //string.h strlen, strcmp, strcpy, atoi, strtok, strcat
61     cout << strlen(s1.c_str()) << endl;//6 abcdef
62 
63     //c_str()是const char*
64     char s3[500];
65     strcpy(s3, s1.c_str());
66     cout << s3 << endl;//abcdef
67 
68     char s4[500];
69     strcpy(s4, s2.c_str());
70     cout << strcmp(s3, s3) << endl;//0
71     cout << strcmp(s3, s4) << endl;//1
72 
73     cout << strcat(s3, s4) << endl;//abcdefThat is a test
74 
75     strcpy(s3, "123");
76     cout << atoi(s3) << endl;//123
77 
78     s1 = "123 456,789,你好";
79     strcpy(s3, s1.c_str());
80     char *p = strtok(s3, " ");
81     while((p = strtok(NULL, ",")))
82     {
83         cout << p << endl;
84         /*
85         123
86         456
87         789
88         你好
89         */
90     }
91     return 0;
92 }