string、char *、char []之間的相互轉換

最近工作中遇到了string、char *、char []之間的相互轉換，今天終於抽出時間將他們之間的轉換記錄下來，使用的是CodeBlocks軟件，編譯器爲GNU GCC compiler，下面看代碼：

#include <iostream>
#include <stdio.h>
#include <string.h>
#include <thread>
#include <stdlib.h>

using namespace std;

int main() {
    //string --> char *
    string str1 = "hello";
    char *p1 = const_cast<char *>(str1.c_str());

    printf("p1=%s.\n", p1);

    //string --> char c[]
    string str2 = "world";
    char c[10] = {0};

    int len1 = str2.size();
    int i = 0;
    for (i = 0; i < len1; ++i) {
        c[i] = str2[i];
    }
    c[i] = '\0';

    printf("c=%s.\n", c);

    //char c[] --> string
    char c2[10] = "great";
    string str3 = c2;
    cout << "str3=" << str3 << endl;

    //char * --> string
    char *p2 = "wall";
    string str4 = p2;
    cout << "str4=" << str4 << endl;

    //char * -->char []
    char *p3 = "china";
    char c3[10] = {0};
    int len2 = sizeof(c3);

    strncpy(c3, p3, len2);
    printf("c3=%s.\n", c3);

    //char [] -->char *
    char c4[10] = "haha";
    int len3 = strlen(c4);
    char *p4 = new char[len3+1];
    strncpy(p4, c4, len3);
    printf("p4=%s.\n", p4);

    delete []p4;

    return 0;
}

 

運行結果如下：