Question

c program

//the file's size in bytes
unsigned int fileSize(const char* name){
    return 0;
}

//same as fileSize except if the file is a directory then it recursively finds the size of directory and all files it contains
unsigned int fileSizeRec(const char* name){
    return 0;
}

Answer 1

#include <stdio.h>
#include <sys/stat.h>
#include <dirent.h>
#include <string.h>

//the file's size in bytes
unsigned int fileSize(const char* name){
        struct stat st;
        stat(name, &st);
        return st.st_size;
}

//same as fileSize except if the file is a directory then it recursively finds the size of directory and all files it contains
unsigned int fileSizeRec(const char* name){
    struct stat st;
    stat(name, &st);
    
    // check if this is a file
    if(S_ISREG(st.st_mode)) {
        return fileSize(name);
    } else {
        // to calculate total size of the current directory
        unsigned int directory_size = 0;
        
        // Open current directory
        DIR *pDir;
        if ((pDir = opendir(name)) != NULL) {
                struct dirent *pDirent;
                
                // read directory's content one by one.
                while ((pDirent = readdir(pDir)) != NULL){
                
                        // create the relative path to the file inside folders
                        char buffer[PATH_MAX + 1];
                        strcat(strcat(strcpy(buffer, name), "/"), pDirent->d_name);
                        
                        // If current entry in directory, is another directory
                        // and it is not . or .. (which is for parent and current 
                        // directory) pointers..
                        if (pDirent->d_type == DT_DIR) {
                                if (strcmp(pDirent->d_name, ".") != 0 && strcmp(pDirent->d_name, "..") != 0) {
                                    // recursively find the size of internal directory
                                    directory_size += fileSizeRec(buffer);
                                }
                        } else {
                                // current entry is a file, add its size
                                directory_size += fileSize(buffer);
                        }
                }

                closedir(pDir);
        }
        return directory_size;
    }
}


int main(void) {
  int x = fileSizeRec("..");
  printf("%d", x);
  return 0;
}