VC++ - 身份證檢查程式

#include
#include

using namespace std;

void main(){
char st[10] ;
int it0,A0,A1,A2,A3,A4,A5,A6,A7,A8,CK,cnn;
char T0;

cout << "請輸入您的身份證字號 :" ;
cin >> st;

T0 = st[0];
A1 = (int)st[1]-48;
A2 = (int)st[2]-48;
A3 = (int)st[3]-48;
A4 = (int)st[4]-48;
A5 = (int)st[5]-48;
A6 = (int)st[6]-48;
A7 = (int)st[7]-48;
A8 = (int)st[8]-48;
CK = (int)st[9]-48;

it0 = (int)toupper(T0);
switch(it0){
case 65:case 77:case 87:
A0 = 0;
break;
case 75:case 76:case 89:
A0 = 1;
break;
case 74:case 86:case 88:
A0 = 2;
break;
case 72:case 85:
A0 = 3;
break;
case 84:case 71:
A0 = 4;
break;
case 70:case 83:
A0 = 5;
break;
case 69:case 82:
A0 = 6;
break;
case 68:case 81:case 79:
A0 = 7;
break;
case 67:case 80:case 73:
A0 = 8;
break;
case 66:case 78:case 90:
A0 = 9;
break;
default:
;
}

cnn = 9-((A0+ 8*A1 + 7*A2 + 6*A3 + 5*A4 + 4*A5 + 3*A6 + 2*A7+ 1*A8)%10);
if (CK==cnn)
cout << "正確";
else
cout << "錯誤";

}