compile_error

I have this compile error, not sure what it means "error : two or more data types in declaration of 'main' "

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

/* structure definitions */
    struct process
    {
       char proc[2];
       int D;       /* disk drives */
       int T;       /* tape drives */
       int P;       /* printer */
       int G;       /* graphical platters */
       int Dm;    /* disk drives maximum */
       int Tm;    /* tape drives maximum */
       int Pm;    /* printer maximum */
       int Gm;    /* graphical platters maximum */
    }
    /* the main client program */
    int main ()
   {
   /*
     Total Resources:
     D --- 13 Disk drives
     T --- 15 Tape drives
     P --- 12 Printer
     G --- 13 Graphical platters
    */
     
      int D = 18;
      int T = 17;
      int P = 11;
      int G = 13;
      int i = 0, j = 0, t = 0;
      int Allocated[10][4], Maximum[10][4], Need[10][4], Work[4];
      int finish[10];
      int Finish_Stack[10];
      struct process proc;
   
      FILE *pt;   /* File pointer */
      char cmd;      /* detect  user command for continue or quit */
   
      if(pt = fopen("proc.dat", "r")) == NULL)
      {
         printf("error: fopen() failed on data.txt\n");
         exit(1);    /*file open error handler */
      }
      printf("\nAllocation\tMaximum \tNeed\n");
   
      while(fscanf(pt, "%s%d%d%d%d%d%d%d%d", proc.proc, &proc.D, &proc.T,&proc.P,
                    &proc.G, &proc.Dm, &proc.Tm, &proc.Pm, &proc.Gm)!=EOF)
      {
         Allocated[i][0] = proc.D;
         Allocated[i][1] = proc.T;
         Allocated[i][2] = proc.P;
         Allocated[i][3] = proc.G;
         Maximum[i][0] = proc.Dm;
         Maximum[i][1] = proc.Tm;
         Maximum[i][2] = proc.Pm;
         Maximum[i][3] = proc.Gm;
         
        /* Calculate the Need : need[i,j]=max[i,j]-allocation[i,j] */
         Need[i][0] = Maximum[i][0] - Allocated[i][0];
         Need[i][1] = Maximum[i][1] - Allocated[i][1];
         Need[i][2] = Maximum[i][2] - Allocated[i][2];
         Need[i][3] = Maximum[i][3] - Allocated[i][3];
         D = D - Allocated[i][0];
         T = T - Allocated[i][1];
         P = P - Allocated[i][2];
         G = G - Allocated[i][3];
         
        /* set finish[i] = false for i = 1...n */
         finish[i] = 0;
         printf("\n( %d %d %d %d)\t( %d %d %d %d )\t( %d %d %d %d )\n", Allocated[i][0],
            Allocated[i][1], Allocated[i][2], Allocated[i][3], Maximum[i][0],
            Maximum[i][1], Maximum[i][2], Maximum[i][3], Need[i][0],
            Need[i][1], Need[i][2], Need[i][3]);
         i++;
      } /* end while */
   
    /* set work = available */
      printf("\nAvailable: \n");
      Work[0] = D;
      Work[1] = T;
      Work[2] = P;
      Work[3] = G;
      printf("\n%d %d %d %d\n", Work[0], Work[1], Work[2], Work[3]);
    /*-------------------------------------------------------------*/
   
      printf("\n==================================================================\n");
      i = 0;
      j = 0;
      printf("\n\npress <ENTER> to the next safe statemet\t");
      cmd = getchar();
   
      while (cmd == '\n')
      {
         if((finish[0] == 1) && (finish[1] == 1) && (finish[2] == 1) && 
         (finish[3] == 1) && (finish[4] == 1) &&(finish[5] == 1) && (finish[6] == 1) && (finish[7] == 1) && (finish[8] == 1) && (finish[9] == 1))
         {
            printf("\n\t=================================================\n");
            printf("\n\t\tAll Processes completed successfully\n");
            printf("\t\t\tWith Such a Sequence : \n\n\t\t( ");
            for(t = 0; t < 10; t++)
            {
               printf("P%d ", Finish_Stack[t]);
            }
            printf(")\n\n");
            printf("\t\t\tThe System is SAFE !\n");
            printf("\n\t=================================================\n");
            printf("\n\nProgram Terminated ... \n\n\n");
            exit(1);
         } /* if */
         for(i = 0; i < 10; i++)
         {
            printf("\nChecking Process %d", i);
            printf("\nWork ( %d %d %d %d )\n", Work[0], Work[1], Work[2], Work[3], i);
            printf("Need ( %d %d %d %d )\n", Need[i][0], Need[i][1], Need[i][2], Need[i][3]);
            if((finish[i] == 0) && (Need[i][0] <= Work[0]) && (Need[i][1] <= Work[1])
                                && (Need[i][2] <= Work[2]) && (Need[i][3] <= Work[3]))
            {
               printf("Need <= Work :\n");
               printf("So Doing Process %d\n", i);
               printf("..\n");
               printf("....\n");
               printf("..........\n");
               printf("......................\n");
           
               Work[0] = Work[0] + Allocated[i][0];
               Work[1] = Work[1] + Allocated[i][1];
               Work[2] = Work[2] + Allocated[i][2];
               Work[3] = Work[3] + Allocated[i][3];
               finish[i] = 1;
           
               printf("NOW Process %d DONE !\n\n", i);
               Finish_Stack[j] = i;
               printf("The Process have been done : ");
               for(t = 0; t < = j; t++)
               {
                  printf("P%d ", Finish_Stack[t]);
               } /* end inner for */
               
               printf("\n");
               j++;
               break;
            }
            else
            {
               if(finish[i] == 1)
               {
                  printf("This Work already been done\n");
                  printf("Jump to next process\n");
               }
               else
               {
                  printf("BECAUSE : There were Existing Need > Work\n");
                  printf("---> So, jump to next process\n");
               }
               if(i == 9)
               {
                  printf("\n\t===============================================================\n");
                  printf("\n\t\tAll Process have been checked\n");
                  printf("\t\tThere is no appropriate Process can be processing\n");
                  printf("\t\tSo There was NO Safe State so far\n");
                  printf("\n\t===============================================================\n");
                  printf("\n\nProgram Terminated ... \n\n\n");
                  exit(1);
               }
            }
         }/* end for */
         printf("\n\n\npress <ENTER> to the next safe statemet\t");
         cmd = getchar();
      } /* end while */
     
      /* close the file */
      fclose(pt);
     
      return(0);
   }