一个校验身份证号码合法性的C程序

  出处：Internet   

#include
#include
#include
#include

int IsDigitBuf(char *sBuf, int nLen)
{
    int    i;

    if (nLen == 0) return 1;
    if (nLen > strlen(sBuf)) nLen = strlen(sBuf);

    for (i = 0; i < nLen; i++)
        if (!isdigit(sBuf[i])) return 0;

    return 1;
}

int checkdate(int iYear, int iMonth, int iDay)
{
    if (iYear < 0 || iYear > 9999)
    return -1;
    switch (iMonth)
    {
    case 1:
    case 3:
    case 5:
    case 7:
    case 8:
    case 10:
    case 12:
        if (iDay <= 0 || iDay > 31)
        {
            return -3;
        }
        break;
    case 4:
    case 6:
    case 9:
    case 11:
        if (iDay <= 0 || iDay > 30)
        {
            return -3;
        }
        break;
    case 2:
        if ((iYear % 4 == 0 && iYear % 100 != 0) || iYear % 400 == 0)
        {
            if (iDay <= 0 || iDay > 29)
            {
                return -3;
            }
        }
        else
        {
            if (iDay <= 0 || iDay > 28)
            {
                return -3;
            }
        }
        break;
    default:
        return -2;
    }
    return 0;
}

int CheckStrDate(char *sDate)
{
    int iRet;

    char sYear[5];
    char sMonth[3];
    char sDay[3];

    memset(sYear,  0, sizeof(sYear));
    memset(sMonth, 0, sizeof(sMonth));
    memset(sDay,   0, sizeof(sDay));

    if (strlen(sDate) != 8)
    {
        return -1;
    }

    memcpy(sYear,  sDate, 4);
    memcpy(sMonth, sDate+4, 2);
    memcpy(sDay,   sDate+6, 2);

    iRet = checkdate(atoi(sYear), atoi(sMonth), atoi(sDay));
    if (iRet != 0)
    {
        return -1;
    }

    return 0;
}

int main(int argc, char *argv[])
{
    int    i;
    int    iRet;
    int    iWeight[18] = {7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2, 1};
    char   cCheck[11] = {'1', '0', 'X', '9', '8', '7', '6', '5', '4', '3', '2'};
    char   sIdCardNo[20];
    char   sDate[8 + 1];
    int    iDate;
    int    Sum = 0;

    if (argc < 2) {
        printf("FAIL\n");
        exit(1);
    }

    memset(sIdCardNo, 0, 20);
    memcpy(sIdCardNo, argv[1], 18);
    if ((strlen(sIdCardNo) == 15) && ((iRet = IsDigitBuf(sIdCardNo, 15)) > 0)) {
        printf("OK\n");
        exit(0);
    } else if (strlen(sIdCardNo) != 18) {
        printf("FAIL\n");
        exit(1);
    }

    /* 身份证7-14位是否有效 */
    memset(sDate, 0, sizeof(sDate));
    memcpy(sDate, sIdCardNo + 6, 4);
    iDate = atoi(sDate);
    if (iDate < 1900 || iDate > 2020) {
        printf("FAIL\n");
        exit(1);
    }
    memset(sDate, 0, sizeof(sDate));
    memcpy(sDate, sIdCardNo + 6, 8);
    iRet = CheckStrDate(sDate);
    if (iRet < 0) {
        printf("FAIL\n");
        exit(1);
    }

    /* 身份证18位校验位是否有效 */
    for (i = 0; i < 17; i ++) {
        memset(sDate, 0, sizeof(sDate));
        sDate[0] = sIdCardNo[i];
        iDate = atoi(sDate);
        Sum += iWeight[i] * iDate;
    }
    Sum %= 11;
    if ('x' == sIdCardNo[17]) {
        sIdCardNo[17] = 'X';
    }
    if (cCheck[Sum] != sIdCardNo[17]) {
        printf("FAIL\n");
        exit(1);
    }

    printf("OK\n");
    exit(0);
}