how do you input data from a file into an array?

how do you take data from a file and inputted into an array if the data in the file were to look like this

1 1 1
2 1 1
3 1 1
4 1 1
5 1 1
6 1 1

...and
(column 1) index of the array, i -- an integer;
(column 2) value of element iin array x, x[i] -- a double value
(column 3) value of element i in array y, y[i]


so i for example when i do my first loop i should get this

x[1]=1 y[1]=1

and my second loop

x[2]=1 y[2]=1.


i know how to open file and work with loops, but i dont know how to make my first column the index of the array, and my second column the value of the element and so on. so any help would be appreciated.


so it should look something like this

Code:

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#include <stdio.h>
int main()
{
        FILE *inp;
        int input_status;
        int n;

        inp = fopen("xy.txt", "r"); //opens files
        input_status = fscanf(inp, "&#37;d", &n); //takes digits

        while (input_status != EOF) //loop repeats till end of file
        {
                printf( "%d\n",n);// instead of this i need something that assigns it to i, and to the value of the element in array x, x[i]
                input_status = fscanf(inp, "%d", &n);
                }
                fclose(inp);

}

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Quote:

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Originally Posted by jorgejags

how do you take data from a file and inputted into an array if the data in the file were to look like this

1 1 1
2 1 1
3 1 1
4 1 1
5 1 1
6 1 1

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Are the 1...6 line numbers that you put in or are those present in the file along with the array data?

yeah those are the index of the array.

I guess you have to use the fscanf function twice. First you read the index number, then the two values.

thanks.

You can read each input line with a single fscanf() and do the assignments in the next step as in

Code:

---

#include <stdio.h>
int main(void)
{
        int x[10], y[10];
        FILE *inp;
        int ret, l, m, n;

        inp = fopen("file.txt", "r");
        while ((ret = fscanf(inp, "%d%d%d", &n, &m, &l)) != EOF && ret == 3) {
            x[n-1] = l;
            y[n-1] = m;
            printf("n = %d\nx[%d] = %d\ny[%d] = %d\n", n, n-1, m, n-1, l);
        }
        fclose(inp);
}

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