?

int f(int n, int a[], int idx)
{
?if(n==0) return 1;?
?if(idx==4)? return 0;? //超出數組范圍 出錯

?for(int i=(int)sqrt(n); i>=1; i--)
?{
??a[idx] = i;

??if(f(n-i*i, a, idx+1) == 1)? return 1;? // 遞歸調用
?}

?return 0;
}

int main(int argc, char* argv[])
{
?for(;;)
?{
??int number;
??printf("輸入整數(1~10億)：");
??scanf("%d",&number);

??int a[] = {0,0,0,0};

??int r = f(number, a, 0);

??printf("%d: %d %d %d %d/n", r, a[0], a[1], a[2], a[3]);

?}
?return 0;
}