数组方法（很麻烦）写数列求和题

解题思路:

注意事项:

参考代码:

#include <stdio.h>

int main()

{

    int sum1=0;

    int sum2=0;

    float sum3=0;

    int a,b,c,i;

    scanf("%d %d %d", &a, &b, &c);

    int arr1[a];

    arr1[0] = 1;

    for (i = 0; i < a; i++){

        arr1[i+1] = arr1[i] + 1;

        sum1 = arr1[i] + sum1;

    }

    int arr2[b];

    arr2[0] = 1;

    for (i = 0; i < b; i++){

        arr2[i+1] = arr2[i] + 1;

        arr2[i] = arr2[i]*arr2[i];

        sum2 += arr2[i];

    }

    int arr3[c];

    arr3[0] = 1;

    for (i = 0; i < c; i++){

        arr3[i+1] = arr3[i] + 1;

        sum3 = sum3 + 1.0/arr3[i];

    }

    float sum;

    sum = sum1 + sum2 + sum3;

    printf("%.2f", sum);

    return 0;

}