csu 1031 Parsing Real Numbers

先标记，然后分情况判断，最后一定要多做测试。略显麻烦。

/* 1031: Parsing Real Numbers */
# include <stdio.h>
# include <ctype.h>
# include <string.h>

# define BITSET(i) ((sign)|=(char)(0x1<<(i)))
# define GETBIT(i) ((sign)>>(i) & (0x1))

char a[1000];
char sign;

/* sign: 0 - wrong?
         1 - coeff sign
         2 - integ
         3 - digit
         4 - floatdigit
         5 - e
         6 - e sign
         7 - e integ
*/

int main()
{
    int i, T, len, judge;

    //freopen("in.txt", "r", stdin);
    //freopen("out.txt", "w", stdout);

    scanf("%d", &T);
    while (T > 0)
    {
        scanf("%s", a);
        len = strlen(a);

        sign = 0;
        i = 0;
        if (a[i]=='+' || a[i]=='-') { BITSET(1); ++i;}
        while (isdigit(a[i])) { BITSET(2); ++i;}
        if (a[i]=='.') { BITSET(3); ++i;}
        while (isdigit(a[i])) { BITSET(4); ++i;}
        if (a[i]=='E' || a[i]=='e') { BITSET(5); ++i;}
        if (a[i]=='+' || a[i]=='-') { BITSET(6); ++i;}
        while (isdigit(a[i])) { BITSET(7); ++i;}

        if ((a[i] != '\0')
                || (GETBIT(3) && !GETBIT(2) && !GETBIT(4))
                || ((GETBIT(5)||GETBIT(6)) && !GETBIT(7))
                || (len && !GETBIT(2) && !GETBIT(4)))
            BITSET(0);

        if (GETBIT(0)) printf("NO\n");
        else printf("YES\n");
        --T;
    }

    return 0;
}