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To read the CSV file in C
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
void read_csv(int row, int col, char *filename, double **data){
FILE *file;
file = fopen(filename, "r");
int i = 0;
char line[4098];
while (fgets(line, 4098, file) && (i < row))
{
// double row[ssParams->nreal + 1];
char* tmp = strdup(line);
int j = 0;
const char* tok;
for (tok = strtok(line, "\t"); tok && *tok; j++, tok = strtok(NULL, "\t\n"))
{
data[i][j] = atof(tok);
printf("%f\t", data[i][j]);
}
printf("\n");
free(tmp);
i++;
}
}
int main(int argc, char const *argv[])
{
/* code */
if (argc < 3){
printf("Please specify the CSV file as an input.\n");
exit(0);
}
int row = atoi(argv[1]);
int col = atoi(argv[2]);
char fname[256]; strcpy(fname, argv[3]);
double **data;
data = (double **)malloc(row * sizeof(double *));
for (int i = 0; i < row; ++i){
data[i] = (double *)malloc(col * sizeof(double));
}
read_csv(row, col, fname, data);
return 0;
}
@angysinghdhillon
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angysinghdhillon commented Jun 20, 2018

where and how do i mention the file name

@manoharmukku
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manoharmukku commented Jul 18, 2018

You need to pass the file name as the command line argument while running the program.
For example
./a.out 500 15 data_file.csv
where a.out is the executable, 500 is the number of rows, 15 is the number of columns and data_file.csv is the file name which is present in the current directory.

@divyangarora1
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divyangarora1 commented Nov 25, 2018

This code is reading only one row .

@tomasrojasc
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tomasrojasc commented Dec 19, 2018

indeed is reading only one row and filling the rest with zeros. Did someone managed to finish the function?

@kiviodepaula
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kiviodepaula commented Mar 1, 2021

The code it's working fine, but you need to customize it according your csv file. In my case, the values were separeted by ",", so I needed to change the code as follow:

for (tok = strtok(line, ","); tok && *tok; j++, tok = strtok(NULL, ","))

@lou8085
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lou8085 commented Jun 9, 2021

Very helpful program. Thank you !!

@Willespinosa13
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Willespinosa13 commented Jun 21, 2021

Thank you @manoharmukku.
the code is run using linux, right?

@lou8085
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lou8085 commented Jun 21, 2021

I ran it under Windows 10 using gcc

@manoharmukku
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manoharmukku commented Jun 22, 2021

Thank you @manoharmukku.
the code is run using linux, right?

The code can be run in any command line (terminal) which has gcc. It works for Linux, MacOS and Windows.

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