在一个字符串中找到第一个只出现一次的字符。如输入abaccdeff，则输出b

在一个字符串中找到第一个只出现一次的字符。如输入abaccdeff，则输出b

char FirstOnce(char* sz)
{
if (!sz || *sz = 0) return '\0';
unsigned short bm[256] = {0};

unsigned short m = 0;
while (*sz) {
if (!bm[*sz]&0xFF) {
bm[*sz] = 0x0;
bm[*sz] |= 0x01;
bm[*sz] |= (++m) << 8;
}
else {
bm[*sz] &= ~0xFF;
bm[*sz] |= 0x02;
}
}

unsigned short min = 0xFFFF;
char c = '\0';
for (int i=0; i<256; i++) {
if (bm[i] & 0xFF != 0x01) continue;
if (min > bm[i] & 0xFF00 >> 8) {
min = bm[i] & 0xFF00 >> 8;
c = i;
}
}

return c;
}