#include<stdio.h>#include<signal.h>#include<sys/time.h>#include<errno.h>#include<setjmp.h>#include<string.h>#include<stdlib.h>#include<unistd.h>unsigned int sleep(unsigned int );//returns:0 or number of seconds  main(int argc,char **argv){	int n,i;	if(argc<2)	{		fprintf(stderr,"Usage: %s <period(S)>\n");		exit(0);	}	for(i=1;i<argc;i++)	{		if(sscanf(argv[1],"%d",&n)!=1)		{ printf("Not a valid number\n"); exit(225);  }		sleep(n);		n=0;	}	return 0;}