26 lines
700 B
C
26 lines
700 B
C
|
|
int decchk(string,n,ch)
|
|
char *ch,string[];
|
|
int n;
|
|
{
|
|
char c;
|
|
int j,k=0,m=0;
|
|
static int ip[10][8]={0,1,5,8,9,4,2,7,1,5, 8,9,4,2,7,0,2,7,0,1,
|
|
5,8,9,4,3,6,3,6,3,6, 3,6,4,2,7,0,1,5,8,9, 5,8,9,4,2,7,0,1,6,3,
|
|
6,3,6,3,6,3,7,0,1,5, 8,9,4,2,8,9,4,2,7,0, 1,5,9,4,2,7,0,1,5,8};
|
|
static int ij[10][10]={0,1,2,3,4,5,6,7,8,9, 1,2,3,4,0,6,7,8,9,5,
|
|
2,3,4,0,1,7,8,9,5,6, 3,4,0,1,2,8,9,5,6,7, 4,0,1,2,3,9,5,6,7,8,
|
|
5,9,8,7,6,0,4,3,2,1, 6,5,9,8,7,1,0,4,3,2, 7,6,5,9,8,2,1,0,4,3,
|
|
8,7,6,5,9,3,2,1,0,4, 9,8,7,6,5,4,3,2,1,0};
|
|
|
|
for (j=0;j<n;j++) {
|
|
c=string[j];
|
|
if (c >= 48 && c <= 57)
|
|
k=ij[k][ip[(c+2) % 10][7 & m++]];
|
|
}
|
|
for (j=0;j<=9;j++)
|
|
if (!ij[k][ip[j][m & 7]]) break;
|
|
*ch=j+48;
|
|
return k==0;
|
|
}
|