写一个C语言的直方图增强代码

以下是一个简单的C语言直方图增强代码示例：

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

#define MAX_PIXEL_VALUE 255

int main()
{
    int width, height, max_val;
    scanf("%*s %d %d %d", &width, &height, &max_val);

    int *histogram = (int*)calloc(MAX_PIXEL_VALUE + 1, sizeof(int));
    int *cumulative_histogram = (int*)calloc(MAX_PIXEL_VALUE + 1, sizeof(int));

    for (int i = 0; i < width * height; i++)
    {
        int pixel_value;
        scanf("%d", &pixel_value);
        histogram[pixel_value]++;
    }

    cumulative_histogram[0] = histogram[0];
    for (int i = 1; i <= MAX_PIXEL_VALUE; i++)
    {
        cumulative_histogram[i] = cumulative_histogram[i - 1] + histogram[i];
    }

    for (int i = 0; i < width * height; i++)
    {
        int pixel_value;
        scanf("%d", &pixel_value);
        int new_pixel_value = (int)(((float)cumulative_histogram[pixel_value] / (float)(width * height)) * MAX_PIXEL_VALUE);
        printf("%d ", new_pixel_value);
    }

    free(histogram);
    free(cumulative_histogram);

    return 0;
}

这个代码可以读取一个PGM格式的图像文件，计算其直方图并进行直方图均衡化，输出处理后的图像。