Reading lines from CSV file and separating into values (sscanf SIGSEGV)

Question

I have been working on a program that wants to read 10 lines from a csv file and separate the name and the grade. I have used the documentation provided here Reading values from CSV file into variables

Unfortunately, my code throws a SIGSEGV when coming to the line with the sscanf statement. I have tried to remove the , between %[^,] and %f, after which it works but only gets the names, not the grades, which defeats the purpose.

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

int main() {
    char str[10][30], names[10][20];
    FILE *fp;
    int i; 
    float grades[10];

    fp = fopen("names.txt", "rt");

    for (i = 0; i < 10; i++) {
        fgets(str[i], 30, fp);
        sscanf(str[i], "%[^,], %f", &names[i], grades[i]);
        printf("%s ", names[i]);
        printf("%f ", grades[i]);
    };
}

This is the content of the csv file:

Bob,8
Carla,7
Jack,5
Julie,3
Goncalo,9
Vera,6
Jesse,8
James,8
Francis,10
Monica,6

Thank you for your help, if you need any other information please don't hesitate to ask.

It worked, but why is the ampersand not necessary here? While in the other thread it was there? — Casz146, Aug 17 '16 at 16:21

score 1 · Accepted Answer · answered Aug 17 '16 at 17:20

The arguments to your sscanf are incorrect, its should be:

sscanf(str[i], "%19[^,], %f", names[i], &grades[i]);

names[i] is a char array, so you should not pass its address, but the address of its first element, which is either &names[i][0] or simply names[i].

Conversely, grades[i] is a float. You must pass its address as &grades[i] or possibly grades + i, but it is less readable.

And you should check the return value to verify in the input string was correctly converted.

Also remove the extra ; at the end of the for block.

Reading lines from CSV file and separating into values (sscanf SIGSEGV)

1 Answers1