斐波那契数列

#include <stdio.h>

// 递归函数来计算斐波那契数列的第n项
int fibonacci(int n) {
    if (n <= 1)
        return n;
    return (fibonacci(n - 1) + fibonacci(n - 2));
}

int main() {
    FILE *file = fopen("fab.txt", "w");
    if (file == NULL) {
        printf("cannot open this file");
        return 1;
    }

    int n = 20;
    int sum = 0;

    printf("前20项斐波那契数列：\n");
    fprintf(file, "前20项斐波那契数列：\n");
    
    for (int i = 0; i < n; i++) {
        int fib = fibonacci(i);
        printf("%d ", fib);
        fprintf(file, "%d ", fib);
        sum += fib;
    }

    printf("\n前20项斐波那契数列之和：%d\n", sum);
    fprintf(file, "\n前20项斐波那契数列之和：%d\n", sum);

    fclose(file);
    
    return 0;
}