Java程序猿学习C++之字符串

#include <iostream>
#include <string.h>
using namespace std; int my_len(const char *str)
{
int len = 0;
// while (*str != '\0')
// {
// ++len;
// ++str;
// } while (*(str++) != '\0')
{
++len;
} return len;
} void my_cpy(char *dst,const char *src)
{
while (*src != '\0')
{
*dst = *src;
++dst;
++src;
}
} int main()
{
char str1[] = "abc";//后面自己主动加上'\0'
char str2[] = { 'a', 'b', 'c' };//后面不会自己主动加上个'\0',作为字符串会一直找到'\0'标志
char str3[] = { 'a', 'b', 'c' ,'\0'};
char str4[10] = "abc"; // 4 3 4 10
cout << sizeof(str1) << "," << sizeof(str2) << "," << sizeof(str3) << "," << sizeof(str4) << endl;
// 3 15 3 3
cout << strlen(str1) << "," << strlen(str2) << "," << strlen(str3) << "," << strlen(str4) << endl;
cout << my_len(str1) << "," << my_len(str2) << "," << my_len(str3) << "," << my_len(str4) << endl; // abc abc烫烫烫烫蘟bc abc abc
cout << str1 << "," << str2 << "," << str3 << "," << str4 << endl; //字符串赋值
//str1 = str2;// 错误。数组名是地址常量
//str1 = "hello";// 错误。数组名是地址常量
strcpy(str4,str1); //strcmp(str1,str2);字符串比較
//strcat(str3,str2);字符串拼接,必须推断空间是否够 //字符串切割
char str[] = "this is a test";
char *token = strtok(str, " ");
while (token != NULL)
{
cout << token << endl;
token = strtok(NULL," ");
} return 0;
}

c++风格字符串

#include <iostream>
#include <string>
using namespace std; int main()
{
string str1 = "hello";
string str2 = "abc";
string str3 = "abc"; //拷贝赋值
str3 = str1;
cout << str1 << "," << str3 << endl; //获取长度
cout << str1.length() << endl; //字符串的比較
str1.compare(str3); //字符串拼接
str3 += str2; //字符串切割
string str4 = "this is a test";
//转换为c风格的string
//char *token = strtok((char *)str4.c_str(), " ");//强制类型转换
char *token = strtok(const_cast<char *>(str4.c_str()), " ");
while (token != NULL)
{
cout << token << endl;
token = strtok(NULL, " ");
} //遍历字符串(string::size_type i = 0; i < str1.length();i++)
for (string::size_type i = 0; i < str1.length(); i++)
{
cout << str1[i] << "-" ;
}
cout << endl; for (string::size_type i = 0; i < str1.length(); i++)
{
cout << str1.at(i) << "-";
}
cout << endl; for (string::iterator itr = str1.begin(); itr != str1.end();++itr)
{
cout << *itr << "-";
}
cout << endl; int cnt = 0;
while (cnt < 50)
{
if (str1.size() == str1.capacity())
{
//cout << "hhh";
}
str1.push_back('*');
cnt++;
//cout << str1.size() << "," << str1.capacity() << endl;
} str1.clear();
if (str1.empty())
{
cout << "str1.empty";
} return 0;
}
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