/* C program for fibonacci numbers */
#include <stdio.h>
#include <string.h>

int main() {

	FILE *outfile;
	/*string filename;*/
	char filename[30];
	int num;
	int newnum;
	int latest;
	int prev;
	int guess;
	printf("What is the name of your output file? \n");
	/* filename = GetLine(); */
	scanf("%s",filename);
	outfile = fopen(filename,"w");
	/* should check success */
	if (outfile == NULL) {
		printf("Error - can't open the file: %s \n",filename);
	}
	else {
		printf("How many numbers to list? \n");
		scanf("%d",&num);
		if (num < 2) {
			printf ("Must show at least 2 numbers, try again later"); 
		}
		else {
			latest = 1;
			prev = 1;
			fprintf(outfile,"The numbers are: \n");
			fprintf(outfile,"      %d  %d",prev, latest);
			printf("The numbers are: \n");
			printf("      %d  %d",prev, latest);
			while (num > 2) {
				newnum = latest + prev;
				fprintf(outfile,"  %d ",newnum);
				printf("  %d ",newnum);
				prev = latest;
				latest = newnum;
				num--;
			}
			printf("\n What do you think the next number will be? ");
			scanf("%d",&guess);
			newnum = latest + prev;
			if (guess == newnum){
				printf("\n Congratulations, you are correct \n");
				fprintf(outfile,"\n Congratulations, you are correct \n");
			}
			else {
				printf("\n Sorry, your guess of %d is incorrect, the correct answer is %d \n",
					guess,newnum);
				fprintf(outfile,"\n Sorry, your guess of %d is incorrect, the correct answer is %d \n",
					guess,newnum);
			}
		}
	}
	return 0;
}