#include <dirent.h>
    #include <stdio.h>
    #include <string.h>
    #include <sys/types.h> /* include necessary header files */
    #include <fcntl.h>
    #include <stdlib.h>
    #include <unistd.h>
    #include <time.h>
    #define BUF_SIZE 4096 /* use buffer of 4096 bytes */
    #define OUTPUT_MODE 0700 /*protect output file */
    #define MAX_STR_LEN 256
    int main(void) {
      DIR *d;
      struct dirent *dir;
      char strTemp[256], srcFile[256],
      dstFile[256], srcDir[256], dstDir[256];
      char **ptrFileLst;
      char buffer[BUF_SIZE];
      int nrOfStrs=-1, srcFileDesc,
      dstFileDesc, readByteCount,
      writeByteCount, numFiles;
      int indPtrFileAcc, q;
      float nrFilesCopy;
      // vars for generatingRandNumList
      int i, k, curRanNum, curLstInd,
      numFound, numsToGen, largNumRange;
      int *numLst;
      float procFilesCopy;
      printf("Enter name of source Directory\n");
      scanf("%s", srcDir);
      printf("Enter name of destionation Directory\n");
      scanf("%s", dstDir);
      printf("How many files does the directory with mp3 files contain?\n");
      scanf("%d", &numFiles);
      printf("What percent of the files do you wish to make a random selection of\n");
      printf("enter a number between 1 and 88\n");
      scanf("%f", &procFilesCopy);
      // allocate memory for filesList, list of random numbers
      ptrFileLst= (char**) malloc(numFiles * sizeof(char*));
      for (i = 0; i < numFiles; i++) {
        ptrFileLst[i] = (char*)malloc(MAX_STR_LEN * sizeof(char));
      }
      
      largNumRange = numFiles;
      nrFilesCopy = (procFilesCopy / 100) * numFiles;
      numsToGen = (int)((procFilesCopy / 100) * numFiles);
      printf("nrFilesCopy=%f", nrFilesCopy);
      printf("NumsToGen=%d", numsToGen);
      numLst = malloc(numsToGen * sizeof(int));
      srand(time(0));
      numLst[0] = rand() % largNumRange + 1;
      numFound=0;
      do { 
        curRanNum = (int)rand() % largNumRange + 1;
        if (numLst[0] == curRanNum) {
          numFound=1; 
        }
      } while(numFound == 1);
      numLst[1] = curRanNum;
      getchar();
      curLstInd = 1;
      i = 0;
      while(1) {
        do {
          numFound = 0;
          curRanNum = (int)rand() % largNumRange + 1;
          for (int k = 0; k <= curLstInd; k++){
            if (numLst[k] == curRanNum)
            numFound = 1;
          }
        } while(numFound == 1);
        numLst[curLstInd+1] = curRanNum;
        curLstInd++;
        i++;
        // numsToGen=Total numbers to generate minus two
        // already generated by the code above this loop
        if (i == (numsToGen-2))
          break;
        }
        d = opendir(srcDir);
        if (d) {
          while ( (dir = readdir(d)) != NULL ) {
          strcpy(strTemp, dir->d_name);
          if (strTemp[0] != '.') {
            nrOfStrs++;
            strcpy(ptrFileLst[nrOfStrs], strTemp);
          } 
        }
        closedir(d); 
      }
      for (q = 0; q <= curLstInd; q++) {
        indPtrFileAcc = numLst[q];
        strcpy(srcFile, srcDir);
        strcat(srcFile, "/");
        strcat(srcFile, ptrFileLst[indPtrFileAcc]);
        strcpy(dstFile, dstDir);
        strcat(dstFile, "/");
        strcat(dstFile, ptrFileLst[indPtrFileAcc]);
        
        srcFileDesc = open(srcFile, O_RDONLY);
        dstFileDesc = creat(dstFile, OUTPUT_MODE);
        while(1) {
          readByteCount = read(srcFileDesc, buffer, BUF_SIZE);
          if (readByteCount <= 0) 
            break;
          
          writeByteCount = write(dstFileDesc, buffer, readByteCount);
          if(writeByteCount <= 0)
            exit(4);
        }
        //close the files 
        close(srcFileDesc);
        close(dstFileDesc); 
      }
    }

    while(1) {
      readByteCount = read(srcFileDesc, buffer, BUF_SIZE);
      if (readByteCount <= 0) 
        break;
      writeByteCount = write(dstFileDesc, buffer, readByteCount);
      if (writeByteCount <= 0)
          exit(4); 
    }