1304因子求和

#include <stdio.h>int main(int argc,char const *argv[]){    // 0 0 1 1 2 4    int n;    scanf("%d",&n);    int i;    int a=0,b=0,c=1;    int term=1;    int sum=0;    n-=2;    while(n>0&&n--)    {        sum+=c;        int temp=a+b+c;        a=b;        b=c;        c=temp;    }    printf("%d",sum);    return 0;}