#include <stdio.h>
#include<malloc.h>
#include <stdlib.h>
 
int main() {
 
char firstCharacter, secondCharacter;
unsigned int padding;
int image_size,FileSize,reserved,size,width,height,planes,bit_count,compression,data_offset;
 
 FILE * fp = fopen("C:\\jellyfish.bmp","rb");
 
 fread (&firstCharacter, sizeof(char), 1 ,fp);
 
 fread (&secondCharacter, sizeof(char), 1 ,fp);
 
 fread (&FileSize, sizeof(int), 1 ,fp);
 
 fread (&reserved, sizeof(int), 1 ,fp);
 
 fread (&data_offset, sizeof(int), 1 ,fp);
 
 fread (&size, sizeof(int), 1 ,fp);
 
 fread (&width, sizeof(int), 1 ,fp);
 
 fread (&height, sizeof(int), 1 ,fp);
 
 fread (&planes, sizeof(int), 1 ,fp);
 
 fread (&bit_count, sizeof(int), 1 ,fp);
 
 fread (&compression, sizeof(int), 1 ,fp);
 
 fread (&image_size, sizeof(int), 1 ,fp);
 
 printf("first character is %c \n", firstCharacter);
 
 printf("second character is %c \n", secondCharacter);
 
 printf("file size is %d \n", FileSize);
 
 printf("reserved is %d \n", reserved);
 
 printf("data offset is %d \n", data_offset);
 
 printf("size is %d \n", size);
 
 printf("file width is %d \n", width);
 
 printf("file height is %d \n", height);
 
 printf("planes are %d \n", planes);
 
 printf("bit_count is %d \n", bit_count);
 
 printf("compression is %d \n", compression);
 
 printf("image_size is %d \n", image_size);
 
 fclose(fp); //always close the file whe you close

FILE * wp = fopen ("E:\\newfile.bmp", "wb");

char *image_data =(char*)malloc (image_size); //malloc is set to void

padding = 8-((width*3)%8);

int a=width*3+padding;

fread (image_data, image_size, 1, fp);
for(int i=0; i<width; i=+3)
 for(int j=0; j<height; j=+3)
{
 image_data[i*(width+padding)+j] = 0; // B color of first pixel
}

fwrite (&firstCharacter, sizeof(char), 1, wp);

fclose (wp);

free ((void*)image_data);
}

//write header information same as u read
//write image pixel data which is already changed fwrite(&image_data, size,1, wp); fclose(wp); free (image_data);

 
 
형말대로 j++ 를 .. j=+3이렇게 하는거임?

일단 뭐하는프로그래밍냐면
bmp파일을 불러서 정보를 조금 프린트한다음.
RGB 에서 BLUE 요소를 0 즉 검은색으로 변형 후 newfile.bmp 라는 파일을 생성하는거...