字符串和string

字符串变量

字符串常量

字符表示说明

Unicode编码

字符串的指针表示

# include <string.h>
#include <iostream>
using namespace std;
int main()
{
    // 定义一个数组
     char strHelloWorld[11] = { "helloworld" };     // 这个定义可以
     char* pStrHelloWrold = "helloworld";
     pStrHelloWrold = strHelloWorld;
     //strHelloWorld = pStrHelloWrold;               // 数组变量的值不允许改变
     // 字符0, '\0', '0'的区别
     //char c1 = 0;
     //char c2 = '\0';
     //char c3 = '0';
     // 通过数组变量遍历修改数组中的元素值
     for (int index = 0; index <  strlen(strHelloWorld); ++index)
     {
         strHelloWorld[index] += 1;
         std::cout << strHelloWorld[index] << std::endl;
     }
     // 通过指针变量遍历修改数组中的元素值
     for (int index = 0; index < strlen(strHelloWorld); ++index)
     {
         pStrHelloWrold[index] += 1;
         std::cout << pStrHelloWrold[index] << std::endl;
     }
     cout << endl;  // 换行
     // 计算字符串长度
     cout << "字符串长度为: " << strlen(strHelloWorld) << endl;
     cout << "字符串占用空间为:  " << sizeof(strHelloWorld) << endl;
    return 0;
}

字符串的常见操作

#include <string.h>                    //使用C库的头文件
#include <iostream>
using  namespace std;
const unsigned int MAX_LEN_NUM = 16;
const unsigned int STR_LEN_NUM = 7;
const unsigned int NUM_TO_COPY = 2;
int main()
{
    char strHelloWorld1[ ] = { "hello" }; 
    char strHelloWorld2[STR_LEN_NUM] = { "world1" };
    char strHelloWorld3[MAX_LEN_NUM] = {0};
    //strcpy(strHelloWorld3, strHelloWorld1);                                    // hello
    strcpy_s(strHelloWorld3, MAX_LEN_NUM, strHelloWorld1);
    //strncpy(strHelloWorld3, strHelloWorld2, NUM_TO_COPY);      // wollo
    strncpy_s(strHelloWorld3, MAX_LEN_NUM,  strHelloWorld2, NUM_TO_COPY);
    //strcat(strHelloWorld3, strHelloWorld2);                                    //  wolloworld1
    strcat_s(strHelloWorld3, MAX_LEN_NUM, strHelloWorld2);
    //unsigned int len = strlen(strHelloWorld3);
    unsigned int len = strnlen_s(strHelloWorld3, MAX_LEN_NUM);
    for (unsigned int index = 0; index < len; ++index)
    {
        cout << strHelloWorld3[index] << " ";
    }
    cout << endl;    
    // 小心缓冲区溢出
    //strcat(strHelloWorld2, "Welcome to C++");
    strcat_s(strHelloWorld2, STR_LEN_NUM, "Welcome to C++");
    return 0;
}

字符串操作中存在的问题

string简介