This is wcat

wcat.c

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>
#include <string.h>
#include <sys/stat.h>
#include <fcntl.h>


int main(int argc, char const *argv[])
{
	int fp;
	char buf[100];
	int len;
	char error[100]="wcat: cannot open file\n";
	if(argc == 1){return 0;}
	for(int i=1; i<argc; i++){
		fp = open(argv[i], S_IRUSR);

		if (fp== -1){
			for(int i=0;i<100;i++){
				if (error[i]=='\0') break;
				write(1, error+i, 1);
			}
			_Exit(1);
		}
		len = read(fp, buf, 100);
		while(len > 0){
			write(1, buf, len);
			len = read(fp, buf, 100);
		}
	}
	_Exit(0);
	return 0;
}