C Turning lines of an archive into arrays - c

Question

I have an archive and I want to turn every line into an array: v[i].data.
However, when I run the code it shows zeros for the arrays.
Is there anything I should change?
Input
1760
02/20/18,11403.7
02/19/18,11225.3
02/18/18,10551.8
02/17/18,11112.7
02/16/18,10233.9
Actual Output
1761
0
Expected Output
1761
02/20/18,11403.7
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <string.h>
typedef struct{
char data[20];
}vetor;
int main(int argc,char *argv[]){
FILE *csv;
if((csv=fopen(argv[1], "r")) == NULL )
{
printf("not found csv\n");
exit(1);
}
long int a=0;
char linha[256];
char *token = NULL;
if(fgets(linha, sizeof(linha), csv)) //counting lines
{
token = strtok(linha, "\n");
a =(1 + atoi(token));
}
printf("%d\n", a);
rewind(csv);
vetor *v;
v=(vetor*)malloc(a*sizeof(vetor));
char linha2[256];
while (fgets(linha2, sizeof(linha2), csv) != 0)
{
fseek(csv, +1, SEEK_CUR);
for(int i=0;i<a;i++)
{
fscanf(csv, "%[^\n]", v[i].data);
}
}
printf("%s\n", v[0].data);
fclose(csv);
return 0;
}

Answer 1

There were a number of mistakes so I went ahead and rewrote the problem areas with comments explaining what I did
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
typedef struct{
char data[20];
}vetor;
int main(int argc,char *argv[]){
FILE *csv;
if((csv=fopen(argv[1], "r")) == NULL )
{
printf("not found csv\n");
exit(1);
}
char line[20];
// Read number of lines
int num_lines = 0;
if (!fgets(line, sizeof(line), csv)) {
printf("Cannot read line\n");
exit(1);
}
char* token = strtok(line, "\n");
num_lines = atoi(token) + 1;
vetor* v = malloc(num_lines * sizeof(vetor));
// Fill in vetor
int i = 0;
while (fgets(line, sizeof(line), csv) != NULL) {
int len = strlen(line);
line[len-1] = '\0'; // replace newline with string terminator
strcpy(v[i].data, line); //copy line into v[i].data
i++;
}
printf("%d\n", num_lines);
for (i = 0; i < num_lines; i++) {
printf("%s\n", v[i].data);
}
return 0;
}
I think the main mistake was a misunderstanding of how best to read in each line of information. If I understood correctly you want each 02/20/18,11403.7 line to be an element in the vetor array.
The easiest way is to simply get each line one at a time with fgets
while (fgets(line, sizeof(line), csv) != NULL)
Change the ending character from newline to the string terminating character '\0'
int len = strlen(line);
line[len-1] = '\0';
Then copy the string into the ith element of vetor and update i for the next iteration of the loop.
strcpy(v[i].data, line);
i++;