Char * to std::string

2018-07-11 05:44 Kavinkumaran imported from Stackoverflow

I have a function :

Char* getlowestnumber(char* str, int n)
{
......
}

I have to convert str from type char* to std::string to perform some string operations.

I tried a lot of things but I couldn't. Do help me out.

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extracting non homogeneous sequential data from xml files in an container

I am trying to extract information groups of different data type from XML file using MSXML6 DOM parser in C++. the xml contains the groups of non homogeneous data containign different data types. I would like to retrieve the different groups of the information clusters in a sequencial format. Which kind of containers is the best here?

Here is the xml file:

<Activity ActivityType = "CENFsfIgpSurfaceActivity" ActivityVendor = "CENIT" Operation = "Operation.1" SimEventType = "CENITEvent" id = "_-18944736">
            <ActivityName>Surface Activity.1</ActivityName>
            <Relation>Unknown</Relation>
            <Event>
                <Syntax>C_VARPUT/JOG_MOTIONTYPE,R8,1</Syntax>
                <Syntax>C_VARPUT/JOG_INTERPOLMODE,R8,0</Syntax>
                <Syntax>C_VARPUT/JOG_SERIAL,R8,0</Syntax>
                <Syntax>JOG/ -0.4125375, -1.6436356, 1.7844436, 4.2006409, 0.7993971, 0.5876199, 1.8000000</Syntax>
                <Syntax>CONFIG/ 0</Syntax>
            </Event>
        </Activity>
        <Activity ActivityType = "DNBRobotMotionActivity" ActivityVendor = "CENIT" Operation = "Operation.1" SimEventType = "IGRIPMove" id = "_-18944736">
            <ActivityName>Surface Activity.1</ActivityName>
            <Target Default = "Cartesian" ViaPoint = "false">
                <BaseWRTWorld>
                    <Position Units = "m" X = "29.672426" Y = "0.5679999981" Z = "-0.776"/>
                    <Orientation Pitch = "0" Roll = "0" Units = "deg" Yaw = "-180"/>
                </BaseWRTWorld>
                <CartesianTarget>
                    <Position Units = "m" X = "-0.676426" Y = "-0.5004420167" Z = "1.046498163"/>
                    <Orientation Pitch = "0" Roll = "0" Units = "deg" Yaw = "92.98016434"/>
                    <Config Name = "Posture_1"/>
                    <Tag TrackTag = "false">Pt.15104</Tag>
                </CartesianTarget>
                <JointTarget>
                    <Joint DOFNumber = "1" JointName = "J1" JointType = "Rotational" Units = "deg">
                        <JointValue>-23.6367</JointValue>
                    </Joint>
                    <Joint DOFNumber = "2" JointName = "J2" JointType = "Rotational" Units = "deg">
                        <JointValue>-94.1734</JointValue>
                    </Joint>
                    <Joint DOFNumber = "3" JointName = "J3" JointType = "Rotational" Units = "deg">
                        <JointValue>102.2411</JointValue>
                    </Joint>
                    <Joint DOFNumber = "4" JointName = "J4" JointType = "Rotational" Units = "deg">
                        <JointValue>240.6790</JointValue>
                    </Joint>
                    <Joint DOFNumber = "5" JointName = "J5" JointType = "Rotational" Units = "deg">
                        <JointValue>45.8021</JointValue>
                    </Joint>
                    <Joint DOFNumber = "6" JointName = "J6" JointType = "Rotational" Units = "deg">
                        <JointValue>-326.3319</JointValue>
                    </Joint>
                    <AuxJoint DOFNumber = "7" JointName = "Command.1" JointType = "Translational" Type = "RailTrackGantry" Units = "m">
                        <JointValue>1.8</JointValue>
                    </AuxJoint>
                </JointTarget>
            </Target>
            <MotionAttributes>
                <MotionProfile>Default</MotionProfile>
                <ToolProfile>End-Effector Spray Gun-Combo.1.Tool1</ToolProfile>
                <AccuracyProfile>Default</AccuracyProfile>
                <ObjectFrameProfile>Default</ObjectFrameProfile>
                <MotionType>Linear</MotionType>
            </MotionAttributes>
        </Activity>

Iam trying to gather each different activity in one container in the sequence. can CArray of Union of Structs work?

Transform class from C++ to C#

I am new to C# and I need to use a class I had previously in PHP but now I have it in C++, the problem is that I do not know how to transform it to C# in the correct way, I have been trying but I do not get the correct result.

The class should encrypt me the string I enter, for example if I put "HelloDog", you should return the code "C5WXRH0CX9NE10".

This is my original code in C ++:

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>

uint32_t stepa(uint32_t ins)
{
    uint32_t res = 0;
    uint32_t dat;
    uint8_t* key = (uint8_t*)"\x1A\x1F\x11\x0A\x1E\x10\x18\x02\x1D\x08\x14\x0F\x1C\x0B\x0D\x04\x13\x17\x00\x0C\x0E\x1B\x06\x12\x15\x03\x09\x07\x16\x01\x19\x05\x12\x1D\x07\x19\x0F\x1F\x16\x1B\x09\x1A\x03\x0D\x13\x0E\x14\x0B\x05\x02\x17\x10\x0A\x18\x1C\x11\x06\x1E\x00\x15\x0C\x08\x04\x01";
    int i;
    for(i = 0; i < 64; i++)
    {
        dat = ins - (ins & 0xFFFFFFFE);
        ins >>= 1;
        if(dat)
        {
            res += dat << key;
        }
        if(!ins)
        {
            return res;
        }
    }
    return res;
}

void stepb(uint32_t ins)
{
    uint8_t* key = (uint8_t*)"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    uint32_t dat;
    int i;
    for(i = 0; i < 7; i++)
    {
        dat =   
        ins -= ((dat * 9) << 2);
        if(ins < 36)
        {
            printf("%c", key[ins]);
        }
        ins = dat;
    }
}

int main(int argc, char** argv)
{
    if(argc < 2)
    {
        if(argc == 1)
        {
            printf("usage: %s password\n", argv[0]);
        }
        return 0;
    }
    uint8_t len;
    uint8_t i;
    uint8_t xtr;
    uint32_t* dat;

    len = strlen(argv[1]);
    xtr = len % 4;
    if(xtr)
    {
        xtr = 4 - xtr;
    }

    dat = (uint32_t*)malloc(len + xtr);
    memcpy((void*)dat, (void*)argv[1], len);
    if(xtr)
    {
        memset((void*)(((uint8_t*)dat) + len), 0, xtr);
        len += xtr;
    }
    len /= 4;
    for(i = 0; i < len; i++)
    {
        stepb(stepa(dat + 0x3e8));
    }
    printf("\n");
    return 0;
}

And this is the code that I tried to use in C #, it seems that everything is fine but I do not receive any value:

static class Test
{
    private static UInt32 stepa (UInt32 ins)
    {
        UInt32 res = 0;
        UInt32 dat;
        byte[] key = Encoding.Default.GetBytes("\x1A\x1F\x11\x0A\x1E\x10\x18\x02\x1D\x08\x14\x0F\x1C\x0B\x0D\x04\x13\x17\x00\x0C\x0E\x1B\x06\x12\x15\x03\x09\x07\x16\x01\x19\x05\x12\x1D\x07\x19\x0F\x1F\x16\x1B\x09\x1A\x03\x0D\x13\x0E\x14\x0B\x05\x02\x17\x10\x0A\x18\x1C\x11\x06\x1E\x00\x15\x0C\x08\x04\x01");
        int i;
        for (i = 0; i < 64; i++)
        {
            dat = ins - (ins & 0xFFFFFFFE);
            ins >>= 1;
            if (string.IsNullOrEmpty(dat.ToString()))
            {
                res += dat << key[i];
            }
            if (string.IsNullOrEmpty(ins.ToString()))
            {
                return res;
            }
        }
        return res;
    }

    private static void stepb (UInt32 ins)
    {
        byte[] key = Encoding.Default.GetBytes("0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ");
        UInt32 dat;
        int i;
        for (i = 0; i < 7; i++)
        {
            dat = (UInt32)(((UInt64)ins) * 0x38e38e39) >> 35;
            ins -= ((dat * 9) << 2);
            if (ins < 36)
            {
                Console.WriteLine("%c", key[ins]);
            }
            ins = dat;
        }
    }

    public static int encrypt(string argv)
    {
        int len = argv.Length;
        int xtr = len % 4;
        if (string.IsNullOrEmpty(xtr.ToString()))
        {
            xtr = 4 - xtr;
            len += xtr;
        }
        len /= 4;
        for (int i = 0; i < len; i++)
        {
            stepb(stepa((UInt32)argv[i] + 0x3e8));
        }
        return 0;
    }
}

QString replace characters outside of quotes
I'm currently reading in a json file to a QJsonDocument and then converting it to a QString such that it looks like:
```
"thing1":"thing1value",

"thing2":"thing2,value",

"thing3":"thing3value",
```
Each line ends with a comma and I would like to try and format it a bit to show to the user without the quotations and a new line after each line. I was attempting use the replace function to replace any commas with a new line. The problem is that just using the replace function to replace all commas with \n also means that anything inside the quotes is altered too like:
```
"thing2":"thing2

value"
```
Is there any easy way to alter the values exterior of quotes without touching the insides? Is there perhaps a better approach to the overall formatting I could be doing instead? I have a feeling this is asking a bit much of Qt and I may just have to write some function that indexOf finds the first quote and tracks it to the next etc.

Here's what I have so far essentially
```
    QString jDoc = file.readAll();
    file.close();

    QJsonParseError parserError;
    QJsonDocument jsonInit = QJsonDocument::fromJson(jDoc.toUtf8(), &parserError);
    qDebug() << parserError.errorString();
    QString strJson(jsonInit.toJson(QJsonDocument::Indented));
```
How to initialize an std::array of strings?
I have an std::array<std::string, 4> that I want to use to hold path names for text files that I want to read into the program. So far, I declare the array, and then I assign each std::string object the value.
```
#include <array>
#include <string>
using std::array;
using std::string;
...
array<string, 4> path_names;
path_names.at(0) = "../data/book.txt";
path_names.at(0) = "../data/film.txt";
path_names.at(0) = "../data/video.txt";
path_names.at(0) = "../data/periodic.txt";
```
I am using this approach because I know in advance that there are exactly 4 elements in the array, the size of the array will not change, and each path name is hard coded and also cannot change.

I want to declare and initialize the array and all its elements in just one step. For example, this is how I would declare an initialize an array of ints:
```
array<int, 10> ia2 = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};  // list initialization
```
How would I do the same but for std::string? Creating these strings would involve calling the constructor. It's not as simple as just list-initializing a bunch of ints. How to do that?

C++ dynamic vector of string array

I want to create a dynamic vector and each vector element is an array of strings.

The data structure I have in mind is something like this:

VECTOR: 
[0] = [str1, str2, str3]
[1] = [str1, str2, str3]
[2] = [str1, str2, str3]

I correctly insert the values in the res variable BUT my code doesn't work properly: the printing loop is executed 4 times but every time it prints only the LAST element. I believe the problem could be: 1) I don't push the strings array properly in the vector; 2) I don't manage correctly the iteration over the vector and over all the string when I want to print it.

This is my code:

std::vector<std::string*> DatabaseConnector::ExecuteQuery(std::string query, std::vector <std::string> columns)
{
    std::vector<std::string*> results;
    std::string res[columns.size() + 1]; // last value = '\0' to signal end of array

    db_params.res = db_params.stmt->executeQuery(query);
    while (db_params.res->next()) // Access column data by alias or column name
    {
        int i = 0;
        for(std::string s : columns)
            res[i++] = db_params.res->getString(s);

        res[i] = "\0";

        results.push_back(res);
    }

    for(auto el :results)
    {
        int i=0;
        while(el[i].compare("") != 0)
             std::cout << el[i++] << " ";

        std::cout << std::endl;
    }

    return results;
};

How can I get a pointer to the first element of an std::string even if it is empty
How can I get a pointer to the first element of an non-const std::string even if it is empty.

I know for sure the string has a capacity greater than one, however, simply using
```
&my_string.front()
```
triggers a "out of range iterator" assertion failure because the string is empty. Using member function
```
data()
```
doesn't fit too, because I want a pointer of type char*, not const char*. I guess I can perform a const_cast here, but that doesn't seem neat.

Is there a better way to do this?

Related questions

Char * to std::string

See also questions close to this topic