[Learning] [Offer to prove safety 12 interview questions: Print to the largest number of bits n 1]

https://blog.csdn.net/sinat_36161667/article/details/80786754

 

bool increment(char * array, int n) {
    int sIndex = n-1;
    array[sIndex] = array[sIndex] + 1;
    int extra = 0;
    for (int i = sIndex; i>=0; i--) {
        int curIndexNum = array[i] - '0' + extra;
        array[i] = array[i] + extra;
        if (10 == curIndexNum) {
            // 达到进位
            if (i == 0) {
                // 超精度了
                return true;
            }
            array[i] = '0';
            extra = 1;
        }
        else {
            // 没到进位，直接返回就好了
            return false;
        }
    }
    return false;
}

void printN(int n) {
    if ( n <= 0 ) {
        return;
    }
    char *array = (char *)malloc(sizeof(char) * n+1);
    memset(array, '0', n);

    while ( !increment(array, n) ) {
        NSString *string_content = [[NSString alloc] initWithCString:(const char*)array
                                                            encoding:NSASCIIStringEncoding];
        NSLog(@"%@\r\n",string_content);
    }
    
}