Thread: Read a file and put an array into 2D array

I have a task. I must create a function which has specific arguments (int readArray(FILE *wp, char *name, int n, double M[n][n]). I must read an array name from a file and put in an array of pointers, then I must read an array and put their value into an array. I try to run my program, but I get a segmentation fault.

Also in my file, I have the second array, so I must know, how to put them to another array(arr2), but I must read from the fifth line. How to do this? I think about using a scanf and in this scanf, I would ask the user from which line he wants to read, but I don't know how to do that. Or maybe I should try to detect string, and if I detect a second-string I would read from a second-string

This is my program

Code:

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


int readArray(FILE *wp, char *name, int n, double M[n][n])
{
    int i = 0, j;
    fscanf(wp, "%s", &name[0]);
    printf("Print name: %s", name);
    return 0;
    for (i = 0; i < n; ++i)
        for (j = 0; j < n; ++j)
            fscanf(wp, "%lf", &M[i][j]);
    printf("Print array: %s", name);

}

int main (int argc, char *argv[])
{
    FILE *wz;                         
    int n = 3;
    char *name[1];
    char *name2[1]; 
    double arr[n][n];
    double arr2[n][n];

    
    if (argc != 2) {                                
    printf("Wrong arguments number\n");
    printf("I should run this way:\n");
    printf("%s source\n",argv[0]);
    exit(1);
    }
    
    if( (wz= fopen(argv[1],"r")) == NULL) {
        printf("Open error %s\n", argv[1]);
        exit(1);
    }

    readArray(wz, *name, n, arr);
    readArray(wz, *name2, n, arr2);    
    
    int fclose(FILE *wz);
    int fclose(FILE *wc);
    
    return 0;
}

This is my text file, which I have:

Code:

arr1
9 8 7
6 5 4
3 2 1
arr2
1 2 3
4 5 6
7 8 9

When I read only name -everything is fine

Code:

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


int readArray(FILE *wp, char *name)
{
    int i = 0, j;
    fscanf(wp, "%s", &name[0]);
    printf("Print name: %s", name);

    return 0;
}

int main (int argc, char *argv[])
{
    FILE *wz;                         
    int n = 3;
    char *name[1];


    
    if (argc != 2) {                                
    printf("Wrong arguments number\n");
    printf("I should run this way:\n");
    printf("%s source\n",argv[0]);
    exit(1);
    }
    
    if( (wz= fopen(argv[1],"r")) == NULL) {
        printf("Open error %s\n", argv[1]);
        exit(1);
    }

    readArray(wz, *name);
    
    int fclose(FILE *wz);
    int fclose(FILE *wc);
    
    return 0;
}

When I read only array, when I use this txt file

Code:

9 8 7
6 5 4
3 2 1

and this program

Code:

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


int readArray(FILE *wp, int n, double M[n][n])
{
    int i, j;
    for (i = 0; i < n; ++i)
        for (j = 0; j < n; ++j)
            fscanf(wp, "%lf", &M[i][j]);
    printf("Two Dimensional array elements:\n");
    for(i=0; i<3; i++) 
    {
        for(j=0;j<3;j++) 
        {
            printf("%f ", M[i][j]);
        }
    }
    return 0;
}

int main (int argc, char *argv[])
{
    FILE *wz;                         
    int n = 3;
    double arr[n][n];

    
    if (argc != 2) {                                
    printf("Wrong arguments number\n");
    printf("I should run this way:\n");
    printf("%s source\n",argv[0]);
    exit(1);
    }
    
    if( (wz= fopen(argv[1],"r")) == NULL) {
        printf("Open error %s\n", argv[1]);
        exit(1);
    }

    readArray(wz, n, arr);
    
    int fclose(FILE *wz);
    int fclose(FILE *wc);
    
    return 0;
}