rem: return found ? 0 : 1;
add: return (found ? 0 : 1);
context: print_env(char *arg){	char **env = environ;		if (arg == NULL) {		// print all environment 'key=value' pairs (one per line)		while (*env)			printf("%s\n", *env++);				return 0;	}	else {		// print only the value of the specified variable		char *s;		int   len   = strlen(arg);		bool  found = false;				while ((s = *env++) != NULL)			if (!strncmp(s, arg, len)) {				char *p = strchr(s, '=');				if (p) {					printf("%s\n", p+1);					found = true;				}			}				return found ? 0 : 1;	}}