histogram of an image C kode

[yasiner]

For a binary file like this, consider

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>

int main()
{
	char filename[100] = { 0 };
	unsigned int histogram[256] = { 0 };
	FILE* infile;

	printf("Enter the image file name: ");
	scanf("%99s", filename);

	if ((infile = fopen(filename, "rb")) == NULL) {
		puts("file error");
		return 1;
	}

	for (int ch = 0; (ch = fgetc(infile)) >= 0; ++histogram[ch % 256]);
	for (int h = 0; h < 256; printf("%i ", histogram[h++]));
	puts("");
}

Actually i need to write this program with my codes. Because it is my homework but i tried with your codes and i couldn't it. i want to fix my codes. Can you help me to fix my codes?
My codes:

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

int get_image(char *filename, int im[][500], int *xsize, int *ysize)
{
FILE *infile;
int i,j;
if((infile=fopen(filename,"r"))!=NULL)
{
fscanf(infile, "%d %d", xsize, ysize);
for (i=0; i<*ysize; i++)
for(j=0; j<*xsize;j++)
fscanf(infile,"%d", &im[i][j]);
return 1; }
else
return 0;
}

void find_histogram(int image[][500], int xsize,int ysize, int hist[256])
{
int i,j;
for(i=0;i<256;hist[i++]=0);
for(i=0;i<ysize;i++)
for(j=0;j<xsize;j++)

hist[image[i][j]++];

}

void print_histogram(int his[256])
{
int i;
for(i=0;i<256;i++)
printf("Hist[%d]=%d\n",i,his[i]);
}

void main(void)
{
char filename[100];
int image[500][500], histogram[256], xsize, ysize,file_ok;
printf("Enter the image file name:");
scanf("%s",filename);
file_ok=get_image(filename, image, &xsize, &ysize);
if(file_ok==0)
{
printf("File error.\n");
}
else{
find_histogram(image, xsize, ysize, histogram);
print_histogram(histogram);

}
system("PAUSE");
}

[yasiner]

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

int get_image(char *filename, int im[][500], int *xsize, int *ysize)
{
	FILE *infile;
	int i,j;
	if((infile=fopen(filename,"r"))!=NULL)
	{
		fscanf(infile, "%d %d", xsize, ysize);
		for (i=0; i<*ysize; i++)
			for(j=0; j<*xsize;j++)
				fscanf(infile,"%d", &im[i][j]);
		return 1; }
	else
		return 0;
}

void find_histogram(int image[][500], int xsize,int ysize, int hist[256])
{
	int i,j;
	for(i=0;i<256;hist[i++]=0);
	for(i=0;i<ysize;i++)
		for(j=0;j<xsize;j++)
		
			hist[image[i][j]++];

}

void print_histogram(int his[256])
{
	int i;
	for(i=0;i<256;i++)
		printf("Hist[%d]=%d\n",i,his[i]);
}

void main(void)
{
	char filename[100];
	int image[500][500], histogram[256], xsize, ysize,file_ok;
	printf("Enter the image file name:");
	scanf("%s",filename);
	file_ok=get_image(filename, image, &xsize, &ysize);
	if(file_ok==0)
	{
		printf("File error.\n");
	}
	else{
		find_histogram(image, xsize, ysize, histogram);
		print_histogram(histogram);
		
	}
	system("PAUSE");
}

[2kaud]

i want to fix my codes. Can you help me to fix my codes?

The premise of your code is wrong. You are assuming the format of the file used is

x y d d d ...

where x, y are the xsize and ysize and d is the date value as decimal values. This would give as an example a file of format

5 5
1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5

but a .png file isn't in this format - and so this simple code can't be used for a file that isn't in the expected format.

[yasiner]

The premise of your code is wrong. You are assuming the format of the file used is

x y d d d ...

where x, y are the xsize and ysize and d is the date value as decimal values. This would give as an example a file of format

5 5
1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5

but a .png file isn't in this format - and so this simple code can't be used for a file that isn't in the expected format.

I wrote a new code but i have a mistake again.

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

int get_image(char *filename, int im[][500], int *xsize, int *ysize)
{
	FILE *infile;
	int i,j;
	if((infile=fopen(filename,"r+"))!=NULL)
	{
		fscanf(infile, "%d %d", xsize, ysize);
		printf("\nwidth: %d, height: %d \n", *xsize,*ysize);

		for (i=0; i<*ysize; i++)
			for(j=0; j<*xsize;j++)
				fscanf(infile,"%d", &im[i][j]);
		return 1; }
	else
		return 0;
}

void find_histogram(int image[][500], int xsize,int ysize, int hist[256])
{
	int i,j;
	for(i=0;i<256;hist[i++] = 0);

	for(i=0;i<ysize;i++)
		for(j=0;j<xsize;j++)
		
			hist[image[i][j]]++;

}

void print_histogram(int hist[256])
{
	int i;
	for(i=0;i<256;i++)
		printf("Hist[%d]=%d\n",i+1,hist[i]);
}

int main()
{
	char filename[100], path[100] = "C:\\Images\\";
	int image[500][500], histogram[256], xsize, ysize,file_ok;
	printf("Enter the image file name:");
	scanf("%s",filename);

	strcat(path, filename);
	strcpy(filename, path);
	strcat(filename, ".ascii.pgn");

	file_ok=get_image(filename, image, &xsize, &ysize);

	if(file_ok==0)
	{
		printf("File error.\n");
	}
	else
	{
		find_histogram(image, xsize, ysize, histogram);
		print_histogram(histogram);
		
	}
	getchar();
	getchar();


}

[2kaud]

Like I said in post #18, with a .png file your algorithm used is not correct. You can't read xsize and ysize from the file and then read numbers. The format of a .png file isn't like that. For a binary file like a .png file you ned to do it similar to the code in post #14.

[yasiner]

Like I said in post #18, with a .png file your algorithm used is not correct. You can't read xsize and ysize from the file and then read numbers. The format of a .png file isn't like that. For a binary file like a .png file you ned to do it similar to the code in post #14.

so, what can ı do for a png or jpg file?

[2kaud]

Use the code in post #14!

[Larnaco]

Thanks for this thread, it helped me aswell

[2kaud]

Thanks for this thread, it helped me aswell

Are you all doing the same course with the same assignment? What, actually, is the assignment?

[VictorN]

Are you all doing the same course with the same assignment?

I guess, no.
All (s)he is doing here at CG is, IMHO, some type of trollng.
Just look at his/her posts!

[Larnaco]

For a binary file like this, consider

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>

int main()
{
	char filename[100] = { 0 };
	unsigned int histogram[256] = { 0 };
	FILE* infile;

	printf("Enter the image file name: ");
	scanf("%99s", filename);

	if ((infile = fopen(filename, "rb")) == NULL) {
		puts("file error");
		return 1;
	}

	for (int ch = 0; (ch = fgetc(infile)) >= 0; ++histogram[ch % 256]);
	for (int h = 0; h < 256; printf("%i ", histogram[h++]));
	puts("");
}

I think this is a good solution