1:#include <stdio.h>

 2: #include <sys/types.h>

 3: #include <sys/resource.h>
 4: 

 5:  
 6: 

 7: int pidarray[10];
 8: 

 9: void createfiles(int ProcessNumber,int ProcessID);
 10: void parent(pid_t pid,int ProcessNumber,int status);

 11: int error(char *er_message);
 12: char *FileName(int ProcessNumber);

 13:  
 14: main()

 15: {
 16:     int ProNumb=1,status;

 17:     pid_t pid;
 18: 

 19:     
 20:     /*Process no1*/

 21:     pidarray[1]=getpid();
 22:     createfiles(ProNumb,getpid());

 23:     /*Creating Process no2*/
 24:     switch(pid=fork())

 25:     {
 26:     case -1:

 27:         error("fork");
 28:     case 0:

 29:         {
 30:         /*Process no2*/

 31:         ProNumb=2*ProNumb;
 32:         pidarray[ProNumb]=getpid();

 33:         createfiles(ProNumb,getpid());
 34:         /*Creating process no4*/

 35:         switch(pid=fork())
 36:         {

 37:         case -1:
 38:             error("fork");

 39:         case 0:
 40:             /*Process no4*/

 41:             ProNumb=2*ProNumb;
 42:             pidarray[ProNumb]=getpid();

 43:             createfiles(ProNumb,getpid());
 44:             pidarray[ProNumb]=0;

 45:             exit(ProNumb);
 46:             break;

 47:         default:
 48:             /*Back to Process no2*/

 49:             wait(&status);
 50:             parent(pid,ProNumb,status);

 51:             /*Creating Process no5*/
 52:             switch(pid=fork())

 53:             {
 54:             case -1:

 55:                 error("fork");
 56:             case 0:

 57:                 /*Process no5*/
 58:                 ProNumb=2*ProNumb+1;

 59:                 pidarray[ProNumb]=getpid();
 60:                 createfiles(ProNumb,getpid());

 61:                 pidarray[ProNumb]=0;
 62:                 execl("/bin/ls","ls",(char *)0);

 63:                 error("exec");
 64:                 break;

 65:             default:
 66:                 /*Back to Process no2*/

 67:                 wait(&status);
 68:                 parent(pid,ProNumb,status);

 69:                 /*Creating Process no6*/
 70:                 switch(pid=fork())

 71:                 {
 72:                 case -1:

 73:                     error("fork");
 74:                 case 0:

 75:                     /*Process no6*/
 76:                     ProNumb=2*ProNumb+2;

 77:                     pidarray[ProNumb]=getpid();
 78:                     createfiles(ProNumb,getpid());

 79:                     pidarray[ProNumb]=0;
 80:                     execl("/bin/date","date",(char *)0);

 81:                     error("exec");
 82:                     break;

 83:                 default:
 84:                     /*Back to Process no2*/

 85:                     wait(&status);
 86:                     parent(pid,ProNumb,status);

 87:                     /*Process no2*/
 88:                     pidarray[ProNumb]=0;

 89:                     exit(ProNumb);
 90:                 }

 91:             }
 92:         }

 93:         break;
 94:         }

 95:     default:
 96:         /*Back to root process*/

 97:         wait(&status);
 98:         parent(pid,ProNumb,status);

 99:         /*Creating process no3*/
 100:         switch(pid=fork())

 101:         {
 102:         case -1:

 103:             error("fork");
 104:         case 0:

 105:             /*Process no3*/
 106:             ProNumb=2*ProNumb+1;

 107:             pidarray[ProNumb]=getpid();
 108:             createfiles(ProNumb,getpid());

 109:             /*Creating process no7*/
 110:             switch(pid=fork())

 111:             {
 112:             case -1:

 113:                 error("fork");
 114:             case 0:

 115:                 /*Process no7*/
 116:                 ProNumb=2*ProNumb+1;

 117:                 pidarray[ProNumb]=getpid();
 118:                 createfiles(ProNumb,getpid());

 119:                 pidarray[ProNumb]=0;
 120:                 exit(ProNumb);

 121:                 break;
 122:             default:

 123:                 /*Back to Process no3*/
 124:                 wait(&status);

 125:                 parent(pid,ProNumb,status);
 126:                 /*Creating process no8*/

 127:                 switch(pid=fork())
 128:                 {

 129:                 case -1:
 130:                     error("fork");

 131:                 case 0:
 132:                     /*Process no8*/

 133:                     ProNumb=2*ProNumb+2;
 134:                     pidarray[ProNumb]=getpid();

 135:                     createfiles(ProNumb,getpid());
 136:                     pidarray[ProNumb]=0;

 137:                     execl("/bin/ls","ls","-a","-s",(char *)0);
 138:                     error("exec");

 139:                     break;
 140:                 default:

 141:                     /*Back to Process no3*/
 142:                     wait(&status);

 143:                     parent(pid,ProNumb,status);
 144:                     /*Creating process no9*/

 145:                     switch(pid=fork())
 146:                     {

 147:                     case -1:
 148:                         error("fork");

 149:                     case 0:
 150:                         /*Process no9*/

 151:                         ProNumb=2*ProNumb+3;
 152:                         pidarray[ProNumb]=getpid();

 153:                         createfiles(ProNumb,getpid());
 154:                         pidarray[ProNumb]=0;

 155:                         execl("/bin/du","du","-a",(char *)0);
 156:                         //error("exec");

 157:                         break;
 158:                     default:

 159:                         /*Back to process no3*/
 160:                         wait(&status);

 161:                         parent(pid,ProNumb,status);
 162:                         pidarray[ProNumb]=0;

 163:                         exit(ProNumb);
 164:                     }

 165:                 }
 166:             }

 167:             break;
 168:         default:

 169:             /*Back to Process no1*/
 170:             wait(&status);

 171:             parent(pid,ProNumb,status);
 172:             pidarray[ProNumb]=0;

 173:             exit(ProNumb);
 174:         }

 175:     }
 176: 

 177: }
 178: 

 179:  
 180: void createfiles(int ProcessNumber,int ProcessID)

 181: {
 182: 

 183:     int i;
 184:     FILE *Fileptr;

 185:     
 186:     Fileptr=fopen(FileName(ProcessNumber),"w");

 187:     fprintf(Fileptr,"Process Number is %d\n",ProcessNumber);
 188:     fprintf(Fileptr,"Process ID is %d\n",ProcessID);

 189:     fprintf(Fileptr,"Process Number PID\n");
 190:     for(i=1;i<ProcessNumber+1;i++)

 191:     {
 192:         if(pidarray[i]!=0)

 193:             fprintf(Fileptr,"%2d %20d\n",i,pidarray[i]);
 194:     }

 195:     
 196:     sleep(ProcessNumber);

 197:     fclose(Fileptr);
 198: 

 199:     
 200: }

 201:  
 202: void parent(pid_t pid,int ProcessNumber,int status)

 203: {
 204:     struct rusage r_usage;

 205:     FILE *Fileptr;
 206: 

 207:     Fileptr=fopen(FileName(ProcessNumber),"a");
 208:     fprintf(Fileptr,"My child process with PID %5d has exited with code %2d\n",pid,status>>8);

 209:     getrusage(RUSAGE_CHILDREN, &r_usage);
 210:     fprintf(Fileptr,"Usertime of my child is %06ld and systemtime is %06ld\n",r_usage.ru_utime.tv_usec, r_usage.ru_stime.tv_usec);

 211:     fclose(Fileptr);
 212: 

 213:  
 214: }

 215:  
 216: 

 217: int error(char *er_message)
 218: {

 219:     perror(er_message);
 220:     exit(1);

 221: }
 222: 

 223:  
 224: char *FileName(int ProcessNumber)

 225: {
 226:     char *name;

 227:  
 228:     switch(ProcessNumber)

 229:     {
 230:     case 1:

 231:         name="File1";
 232:         break;

 233:     case 2:
 234:         name="File2";

 235:         break;
 236:     case 3:

 237:         name="File3";
 238:         break;

 239:     case 4:
 240:         name="File4";

 241:         break;
 242:     case 5:

 243:         name="File5";
 244:         break;

 245:     case 6:
 246:         name="File6";

 247:         break;
 248:     case 7:

 249:         name="File7";
 250:         break;

 251:     case 8:
 252:         name="File8";

 253:         break;
 254:     case 9:

 255:         name="File9";
 256:         break;

 257:     default:
 258:         exit(1);

 259:  
 260:     }

 261:  
 262:     return name;

 263:     
 264: }