CODEWITHSUNDEEP
c
user2053368
user2053368

Reputation: 1

trying to scan in to a 2-d malloc'd array c programming

i've looked through quite a few questions of 2-d malloc'd arrays already but bascially for whatever reason i cannot find a solution.... my google fu sux sorry =(. been using the site all day for syntactual help though thanks to everyone who helps here! =)

anyways i cant seem to get this fscanf to work =/ if someone could help me it would be much appreciated because i cant see any error at all but i know there is one because it is at this point that my program crashes.

    array1 = (int**)malloc((c)*sizeof(int*));
        int a = 0, i = 0;
        for (a = 0; a < c; a++){
            array1[a] = (int*)malloc((c+1)*sizeof(int));

        }
    a=0;

    for(a = 0; a < c; a++){
                for(i = 0; i < c; i++){
                fscanf(ifp, "%d", array1[a][i]);

    }
    }

where c is the maximum size of the array needed. in this case it is set to 3 but i do need it as a variable

Upvotes: 0

Views: 236

Answers (5)

Vaibhav
Vaibhav

Reputation: 5947

You need to read this.

Please develop habit of reading manpages. It helps a lot.

Upvotes: 0

rajneesh
rajneesh

Reputation: 1749

malloc and other syntext is correct, the issue is in reading the value to array

replace this fscanf(ifp, "%d", array1[a][i]);

with

fscanf(ifp, "%d", &array1[a][i]);

Always enable complier warning, and pay heed to it:)

Upvotes: 1

PQuinn
PQuinn

Reputation: 1022

You want:

fscanf(ifp, "%d", &array1[a][i]);
                  ^

Upvotes: 1

David Grayson
David Grayson

Reputation: 87486

fscanf takes pointers, so I would think you need to prepend its third argument with an ampersand. Didn't the compiler warn you about that?

Upvotes: 1

Some programmer dude
Some programmer dude

Reputation: 409356

When using the scanf family of function to read a value, the destination needs to be a pointer. array1[a][i] is not a pointer, it an actual value (which scanf will treat as a pointer and you now entered the territory of undefined behavior).

What you want is &array1[a][i].

PS. You should not cast the returned value of malloc.

Upvotes: 5

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