ca33a_demo_c++_新旧代码的兼容char数组与vector_string相互转换

/*ca33a_demo_c++33_CppPrimer_新旧代码的兼容_txwtech
旧代码：数组和c风格字符串
新代码：vector和string
相互转换：
c风格字符串<- ->string
数组<- ->vector

C3867错误。
https://docs.microsoft.com/zh-cn/cpp/error-messages/compiler-errors-2/compiler-error-c3867?f1url=https%3A%2F%2Fmsdn.microsoft.com%2Fquery%2Fdev15.query%3FappId%3DDev15IDEF1%26l%3DZH-CN%26k%3Dk(C3867)%26rd%3Dtrue&view=vs-2019
const char *str=st.c_str(); c_str后面的括号不要忘记写上

*/

/*ca33a_demo_c++33_CppPrimer_新旧代码的兼容_txwtech
旧代码：数组和c风格字符串
新代码：vector和string
相互转换：
c风格字符串<- ->string
数组<- ->vector

C3867错误。
https://docs.microsoft.com/zh-cn/cpp/error-messages/compiler-errors-2/compiler-error-c3867?f1url=https%3A%2F%2Fmsdn.microsoft.com%2Fquery%2Fdev15.query%3FappId%3DDev15IDEF1%26l%3DZH-CN%26k%3Dk(C3867)%26rd%3Dtrue&view=vs-2019
const char *str=st.c_str(); c_str后面的括号不要忘记写上

*/

#include <iostream>
#include <string>
#include <vector>
using namespace std;

int main()
{
    string st("Hello World");
    st = st + " bill";
    cout <<"c++:string st: "<< st << endl;

    const char *str=st.c_str();//c++转c风格字符串,必须加上const,常字符指针
    cout << "c风格*str: "<<str << endl;
    //getchar();
    const size_t arr_size = 6;
    int int_arr[arr_size] = {0,1,2,3,4,5};
    vector<int> ivec(int_arr, int_arr + arr_size);//数组转vector, int_arr默认指针指向第一个，int_arr + arr_size指向最后一个的后面 [ 开区间，保活。 ）闭区间不包括。前包后不包
    cout << "间隔ivec:" << endl;
    for (vector<int>::iterator itr = ivec.begin(); itr != ivec.end(); ++itr)
    {
        cout << *itr << endl;
    }
    cout << "间隔ivec2:" << endl;
    vector<int> ivec2(int_arr+1,int_arr+4);//2,3,4的数据赋值到vector
    for (vector<int>::iterator itr = ivec2.begin(); itr != ivec2.end(); ++itr)
    {
        cout << *itr << endl;
    }

    return 0;
}

 

 

/*ca33b_demo_c++_txwtech
vector数据放入数组
*/
#include <iostream>
#include <string>
#include <vector>

using namespace std;

int main()
{
    vector<int> ivec;
    int ival;

    cout << "Enter number:(Ctrl+Z to end)" << endl;
    while (cin >> ival)
        ivec.push_back(ival);

    int *parr = new int[ivec.size()];//创建动态数组
    size_t ix = 0;
    for (vector<int>::iterator iter = ivec.begin(); iter != ivec.end(); ++iter, ++ix)
        parr[ix] = *iter;//vector数据放入数组
    for (ix = 0; ix < ivec.size(); ++ix)
    {
        cout <<"vector to 数组" <<*(parr + ix) << endl;
    }
    delete[] parr;
    return 0;
}

 

/*习题4.34—4.35—c++_txwtech
1.读入一组string数据，放入vector
3.vector字符串->字符指针数组,vector每个字符串--创建新的动态字符数组，
4.vector字符串复制到字符数组
5.字符数组放到动态字符指针数组里面
//cin与getline方法，cin遇到空格就默认一个字符串，getline不识别空格，直到回车，默认一个字符串输入结束
while (getline(cin, str))
svec.push_back(str);
*/

/*习题4.34—4.35—c++_txwtech
1.读入一组string数据，放入vector
3.vector字符串->字符指针数组,vector每个字符串--创建新的动态字符数组，
4.vector字符串复制到字符数组
5.字符数组放到动态字符指针数组里面
//cin与getline方法，cin遇到空格就默认一个字符串，getline不识别空格，直到回车，默认一个字符串输入结束
*/
#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <string>
#include <vector>

using namespace std;

int main()
{
    vector<string> svec;
    string str;
    cout << "enter strings: (ctrl+Z) to end" << endl;
    //while (cin >> str) //cin与getline方法，cin遇到空格就默认一个字符串，getline不识别空格，直到回车，默认一个字符串输入结束
    while (getline(cin, str))
        svec.push_back(str);//1
    //创建动态字符指针数组
    //数组里面放的指针
    char **parr = new char*[svec.size()];

    size_t ix= 0;
    for (vector<string>::iterator iter = svec.begin(); iter != svec.end(); ++iter, ++ix)
    {
        char *p = new char[(*iter).size() + 1];//*iter指向的是一个字符串//3
        strcpy(p,(*iter).c_str());//vector转c风格//4
        parr[ix] = p;//动态字符数组赋值给字符指针//5
    }
    cout << "content of vector: " << endl;
    for (vector<string>::iterator iter = svec.begin(); iter != svec.end(); ++iter)
    {
        cout << *iter << endl;
    }
    cout << "Content of charactor arrays: " << endl;
    for (ix = 0; ix != svec.size(); ++ix)
    {
        cout << parr[ix] << endl;
    }
    //每个指针delete
    for (ix = 0; ix != svec.size(); ++ix)
    {
        delete parr[ix];
    }
    delete[] parr;

        //getchar();
    return 0;
}