String, split. c i need help to figure how to do it-CodePudding

i were using gmatch in lua to split items, and the slots into their own table like data[1] data[2] the data come from DB however now that i moved to C i can't find the right way to do that. i already waste like 5 day's trying to figure how to do it.

this is what i were using on lua to split the needed data

`
local function stringsplit(inStr,sep)
    local rettab = {}
    for str in string.gmatch(inStr, "[^;] ") do
        table.insert(rettab, str)
    end
    return rettab
end


here is an example of the the data i need to split correctly

1:200000;2:200001;3:200002

1 , 2 , 3 are the ITEM SLOT : the separator and 200000-200002 the items

so i want to store them separated, "SLOTS" in DATA[1] and ITEMS in DATA[2]  (only has example)

the desired result should be something like

DATA[1] // SLOT
1
2
3


DATA[2] //ITEMS
200000
200001
200002

i'm sorry for my bad english, i tried, i would be so happy if someone know the solution or a way to do it properly thanks you :/

CodePudding user response：

See code below using the strtok() function and my own function mySplit(). Consider creating your own implementation or tweak mySplit() to save the words in an array.

#include <iostream>  
#include <cstring>  
using namespace std;  

#define MAX_STR 128

char* mySplit(char* strg, char delimiter=' ')
{
    if (NULL == strg) return "\n"; // no string to split passed
    
    //cout << " len: " << strlen(strg);
    int len = strlen(strg);
    for(int i=0; i<len; i  ) {
       if (strg[i] == delimiter)
           strg[i] = '\n';
    }
    return strg;
}

int main()  
{  
    char str[MAX_STR] = "This is a string to split";     
    //cout << " Text to Split: " <<endl;  
    //cin.getline(str, 100); // get string to split   
      
    char *ptr; // pointer to iterate over the src string  
    ptr = strtok(str, " "); // use strtok() to split.  
    cout << " \n Split withstring strtok() : \n" << endl;  
    int cnt = 0;    // make sure loops terminate.
    // use while loop to check ptr is not null  
    while (ptr != NULL && cnt < MAX_STR)  
    {  
        cout << ptr  << endl; // print the string token  
        ptr = strtok (NULL, " "); 
          cnt;
    }  
    
    strcpy(str, "Second test string to split using mySplit()");
    ptr = mySplit(str, ' ');
    cout << endl << ptr << endl;
    return 0;  
}

Output: Split withstring strtok() :

This
is
a
string
to
split

Second
test
string
to
split
using
mySplit()

CodePudding user response：

I usually do something like this, which returns a collections of string_views. Which is quite memory efficient. (But it requires the original string to stay in scope).

#include <iostream>
#include <string>
#include <string_view>
#include <vector>

std::vector<std::string_view> split_string(const std::string_view input, char delimiter)
{
    std::vector<std::string_view> splits;

    const char* p{ input.data() };
    const char* word_begin{ p };
    std:size_t len{ 0u };

    for( auto p = input.data(); *p != 0;   p)
    {
        if (*p == delimiter)
        {
            if (len > 0ul) splits.emplace_back(word_begin, len);
            word_begin = p 1;
            len = 0ul;
        }
        else
        {
              len;
        }
    }

    if (len > 0ul) splits.emplace_back(word_begin, len);
    
    return splits;
}


int main()
{
    auto splits = split_string("This is a string to split", ' ');
    for (const auto split : splits)
    {
        std::cout << split << "\n";
    }

    return 0;
}