Prog#220: cat all files

/*
cat all files
Program#220
*/
#include<stdio.h>
main(int argc,char *argv[])
{
int n,i,p;
char a;
if(argc<2)
{
printf("error: no.of arg");
return 0;
}
n=1;
while(n<argc)
{
p=open(argv[n], 0);
if(p==-1)
{
printf("file open error");
return 0;
}
i=read(p,&a,1);
while(i>0)
{
i=write(1,&a,1);
i=read(p,&a,1);
}
close(p);
n++;
}
}