bmp image to matrix (2d array) in c -

i need put bmp (rgb 24 bit) image 2d array, using c language. have written functions, functions work square images. have created structure store pixels:

typedef struct{ int red; int green; int blue; }pixel; 

i have created 2 int extern values y , x store height , width of image. code (i omitted setwidthheight , createnewimage functions because i'm sure work)

int x, y;  int bitmapin(file* fp,/* int height, int width, */ pixel** img1){     long n;     int t;     fseek(fp, 10, seek_set);     fread(&t, 1, 4, fp);            //reads offset , puts in t     fseek(fp, t, seek_set);              int i, p, e;     e=4-((x*3)%4);     if (e==4) {         e=0;     }     (i=y-1; i>=0; i-- ) {         (p=0; p<x; p++) {             n=fread(&img1[i][p].blue, 1, 1, fp);             if (n!=1) {                 return 29;             }             n=fread(&img1[i][p].green, 1, 1, fp);             if (n!=1) {                 return 30;             }             n=fread(&img1[i][p].red, 1, 1, fp);             if (n!=1) {                 return 31;             }         }         fseek(fp, e, seek_cur);     }     return 0; }  pixel** make2dpixelarray(/*int y, int x*/){     pixel** thearray;     thearray=(pixel**) malloc(x*sizeof(pixel*));     (int i=0; i<x; i++) {         thearray[i]=(pixel*) malloc(y*sizeof(pixel));     }     return thearray; }    int main(int argc, const char * argv[]) {    file* fp;     fp=fopen("/users/admin/desktop/immagine5.bmp", "r");     if (fp==null) {         return 20;     }     setwidthheight(fp);               //puts x=width , y=height, works     pixel** img1=make2dpixelarray();  //creates 2d pixel array , memory     bitmapin(fp, img1);               //this function should put values of rgb pixel matrix     createnewimage(fp, img1);        //this function creates new image.     return 0; } 

when image square there no problems when:

• height>width: error "bad_access..." when try read first pixel in bitmapin()
• width>height: first line of pixel ok. left side kind of copy of right side more blue , little green.

could me solving problem?

you've got x , y swapped when fread values array. think. it's not i've tested out or anything. way lazy that.

for (i=y-1; i>=0; i-- ) {     (p=0; p<x; p++) {         n=fread(&img1[i][p].blue 

i walks through y , p walks through x.

when malloc it, set img[x][y]

thearray=(pixel**) malloc(x*sizeof(pixel*)); (int i=0; i<x; i++) {     thearray[i]=(pixel*) malloc(y*sizeof(pixel)); 

general advice: stay away globals, i'd pass in variables have commented out. name variables better t , e. return 29,30,31 values? try enum or #defines names. (and ignore return value afterwards)

the biggest reason bug wasn't apparent naming scheme. , p? come on, pass in sizex, , sizey, , have x , y worker variables. if context wasn't bitmapin(), variables should bitmapsizex. naming important yo.