unix cat 命令实现 c

#include <stdio.h>
void type_onefile(FILE *fp)
{
char ch;
while((ch = fgetc(fp)) != EOF)
{
putchar(ch);
}
}
int main(int argc, char **argv)
{
FILE *fp;

int i;
if (argc == 1)
{
type_onefile(stdin);

}
for (i = 1; i < argc; i++)
{
fp = fopen(argv[i],"r");
if (fp == NULL)
{
fprintf(stderr, "%s:%s can not open.\n",argv[0],argv[i]);
exit(1);
}

type_onefile(fp);
fclose(fp);
}
return 0;
}