determine if a string has all unique characters?

Question

Can anybody tell me how to implement a program to check a string contains all unique chars ?

Answer 1

#include 

#define ARR_SIZE 32

unsigned char charFlag[ARR_SIZE];

void initFlag() {
    int i = 0;

    for (i = 0; i < ARR_SIZE; i++)
        charFlag[i] = 0;

}

int getFlag(int position) {
    int val = 0;
    int flagMask = 1;

    int byteIndex = position / 8;
    int locPos = position % 8;

    flagMask = flagMask << locPos;
//  flagMask = ~flagMask;

    val = charFlag[byteIndex] & flagMask;
    val = !(!val);
//  printf("\nhex: %x\n", val);
    return val;

}

void setFlag(int position) {
    int flagMask = 1;
    int byteIndex = position / 8;
    int locPos = position % 8;

    flagMask = flagMask << locPos;
    charFlag[byteIndex] = charFlag[byteIndex] | flagMask;

}
int isUniq(char *str) {
    int is_uniq = 1;

    do {
        char *lStr = str;
        int strLen = 0;
        int i;

        if (str == 0)
            break;

        while (*lStr != 0) {
            lStr++;
            strLen++;
        }

        initFlag();
        lStr = str;
        for (i = 0; i < strLen; i++) {
            if (getFlag(lStr[i]))
                break;

            setFlag(lStr[i]);
        }

        if (i != strLen)
            is_uniq = 0;

    } while (0);

    return is_uniq;
}

int main() {

    char *p = "abcdefe";
    printf("Uniq: %d\n", isUniq(p));
    return 0;
}