Reading the data file of the first column as a row

Question

I have a dat file like this

AAAA 1861 9 7 0.00 -1.50 -19.50 9999.00 9999.00 9999.00 9999.00 18.20 9999.00 6.70 135.00 8.00 9999.00 9999.00 9999.00 9999 0 193 250180280600000000 BBBBBBBBB 1861 9 7 0.00 -7.50 36.50 9999.00 9999.00 21.40 1018.10 22.60 9999.00 1.00 68.00 2.00 9999.00 9999.00 9999.00 9999 0 193 451720280600000000 VVVVVVVVV 1861 9 7 0.00 -58.50 10.50 9999.00 9999.00 27.50 9999.00 26.90 9999.00 15.40 45.00 6.00 9999.00 9999.00 9999.00 9999 0 193 357610280600000000 SSSSSSSS 1861 9 7 0.00 117.50 13.50 9999.00 9999.00 28.00 1010.30 28.00 9999.00 4.60 158.00 5.00 9999.00 9999.00 9999.00 9999 0 193 370170280600000000 DD 1861 9 7 1.00 -19.50 6.50 9999.00 9999.00 24.70 1014.80 25.30 9999.00 6.70 203.00 2.00 9999.00 9999.00 9999.00 9999 0 193 343600280600000000 E 1861 9 7 1.00 44.50 -28.50 9999.00 9999.00 20.40 9999.00 19.00 9999.00 2.60 135.00 2.00 9999.00 9999.00 9999.00 9999 0 193 218240280600000000 ZZZZZZZZZZZZ 1861 9 7 1.00 -15.50 38.50 9999.00 9999.00 22.00 9999.00 21.90 9999.00 6.70 68.00 2.00 9999.00 9999.00 9999.00 9999 0 193 458840280600000000 

and I would like to save the first column of the file in a row vector. Any idea?

Here is what I tried

 for(int k=0;k<ROW;k++){ INNA >> ID; for(int j=1;j<=COL;j++) INNA >> discardID; IDname[k]= ID; } 

but in id i all columns should be like a unique row.

Thank you very much

Answer 1

Here is how I would decide:

 #include <fstream> #include <strtk.hpp> // http://www.partow.net/programming/strtk std::string filename("your_input_data.txt"); // assuming the file is text std::fstream fs; fs.open(filename.c_str(), std::ios::in); if(fs.fail()) return false; const char *whitespace = " \t\r\n\f"; std::string keyword; std::vector<float> floats; std::vector<string> keywords; // process each line in turn while( std::getline(fs, line ) ) { // remove beginnning and ending whitespace // can prevent parsing problems // from different line endings. strtk::remove_leading_trailing(whitespace, line); // strtk::parse combines multiple delimeters in these cases if( strtk::parse(line, whitespace, keyword, floats ) ) { std::cout << "succeed" << std::endl; // keyword contains the string and the rest of the values // are placed in the floats vector keywords.push_back( keyword ); // you can also process the numbers } } 

Answer 2

Read the entire row, then get the first column.

 #include <string> #include <iostream> #include <sstream> #include <vector> std::vector<std::string> vec; std::string line; while (std::getline(std::cin, line)) { std::istringstream strm(line); std::string firstcol; strm >> firstcol; vec.push_back(firstcol); } 

Answer 3

Or in C, you can only read in the first column and discard the rest. Something like that:

 #include <stdio.h> #include <malloc.h> #include <string.h> int main( ) { FILE * fp = NULL; fp = fopen("filename", "r"); if (!fp) return -1; char buffer[256]; char ** IDname = NULL; int idcount = 0; while (fscanf(fp, "%s %*[^\n]", buffer) == 1) { idcount++; IDname = realloc(IDname, idcount * sizeof * IDname); IDname[idcount - 1] = strdup(buffer); } return 0; }