c++ - Exception writing data into a new file -

my task read yuv file , each component(y,cb,cr) of it, i'm appending data , storing file. have tried below code:

#include <stdio.h> #include <stdlib.h>  void main() {     file *fp=fopen("traffic_1920x1080.yuv","rb");     file *myyuv=fopen("traffic_1920x1088.yuv","ab");     int count=0;     unsigned char *y=(unsigned char*)malloc(sizeof(unsigned char)*1920*1080);     unsigned char *u=(unsigned char*)malloc(sizeof(unsigned char)*(1920/2)*(1080/2));     unsigned char *v=(unsigned char*)malloc(sizeof(unsigned char)*(1920/2)*(1080/2));      unsigned char ypad[1920*8];     unsigned char upad[(1920/2)*4];     unsigned char vpad[(1920/2)*4];      for(int i=0;i<(1920/2)*4;i++)     {         ypad[i]=255;         upad[i]=128;         vpad[i]=128;     }     for(int i=(1920/2)*4;i<1920*8;i++)         ypad[i]=255;     while (!feof(fp))     {         fread(y,sizeof(unsigned char),1920*1080,fp);         fread(u,sizeof(unsigned char),1920/2*1080/2,fp);         fread(v,sizeof(unsigned char),1920/2*1080/2,fp);          fwrite(y, sizeof(unsigned char),1920*1080,myyuv);         fwrite(ypad,sizeof(unsigned char),1920*8,myyuv);          fwrite(u,sizeof(unsigned char),1920/2*1080/2,myyuv);         fwrite(upad,sizeof(unsigned char),1920/2*4,myyuv);          fwrite(v,sizeof(unsigned char),1920/2*1080/2,myyuv);         fwrite(vpad,sizeof(unsigned char),1920/2*4,myyuv);          printf("frame %d created\r",count);         y+=1920*1080;         u+=1920/2*1080/2;         v+=1920/2*1080/2;         count ++;     }     free(y);     free(u);     free(v);      fclose(fp);     fclose(myyuv); } 

howevr above code works fine first loop, in second loop exception

access violation writing location 0x0092f000. 

at line fwrite(y, sizeof(unsigned char),1920*1080,myyuv);

is problem in pointer increment? or else? please reply. in advance.

these increments:

y+=1920*1080; u+=1920/2*1080/2; v+=1920/2*1080/2; 

will increment pointers past end of allocated memory. example, y points start of 1920*1080 bytes of allocated memory. increasing makes point past end of memory. results in reading/writing to/from unallocated memory. that's why access violation.

i don't see reason pointers incremented @ all.

other that, code should check error conditions (did fopen() succeed, etc.)