#include<stdio.h>int check(long long int d){?int sum=0;?int all;?int i;?int f=2;?for(i=20;i>=0;i--){???? all=d/(10^i);???? if((i%2)==1){???? ?all=all*2;???? ?if(all>9){???? ??all=all-9;???}??}??sum=sum+all;??d=d%(10^i);?}?if((sum%10)==0){??f--;?}?return f;}int main(){?long long int a;?printf("請輸入一個卡號：");?scanf("%lld",&a);?int x=check(a);?if(x==1){??printf("成功！\n");?}?else{??printf("失敗!\n");?}}