string

#include<stdio.h>
#include<stdlib.h>

int isDigit(char c) 
{
  if ( c >= '0' && c <='9') return 1;
  else return 0;
}
int isCapital(char c)
{
 if ( c >= 'A' && c <='Z') return 1;
  else return 0;
}
int isLower(char c)
{
 if ( c >= 'a' && c <='z') return 1;
  else return 0;
}
int isLetter(char c)
{
  if ( isCapital(c) || isLower(c) ) return 1;
  else return 0;
}

int valid(char *name)
{
  for ( int i = 0; name[i] != '\0'; i++) {
    if ( !(isLetter(c) || isDigit(c) )) return 0;
  }
  return 1;
}

char *reverse(char *s) 
{
  int i;
  for ( i = 0; s[i]!= '\0'; i++) {}
  char * result = (char *) malloc(sizeof(char) * i);
  i = i-1;
  int j;
  for ( j = 0; i >=0; i--, j++) {
    result[j] = s[i];
  }
  result[j] = '\0';
  return result;
}

void reverse(char *s)
{
  int i;
  for ( i = 0; s[i] != '\0'; i++) {}
  if (i < 2) return;
  i = i-1;
  int j = 0;
  while ( j < i ) {
    s[j] = s[i-j];
    i--;
    j++;
  }
}
int compare(char *s1, char *s2)
{
  int i;
  int j;
  
  for ( i = 0, j=0; s1[i] != '\0' && s2[j] != '\0'; i++, j++) {
    if ( s1[i] > s2[j] ) {
       return 1;
    } else if(s1[i] < s2[j]) {
       return -1;
    }
  }
  // one of string reached \0
  if ( s1[i] < s2[j] ) return -1;
  if ( s1[i] > s2[j] ) return 1;
  if ( s1[i] == s2[j] ) return 0; // both \0
}

bool isSymmetric(char *s)
{
  int j;
  for ( j =0; s[j] != '\0'; j++) {
  }
  if (j < 2) return true;
  int i = 0;
  j = j-1;
  for ( ; i < j; i++, j--) {
    if (s[i] == ' ' || s[i] == ',') {
      i++;
      continue;
    }
    if ( s[j] == ' ' || s[j] == ',') {
      j--;
      continue;
    }
    if ( s[i] != s[j] ) return false;   
  }
  return true;
}
int main() 
{
  char *s = "John";
  for ( int i = 0; s[i]!='\0'; i++) {}
  printf("The lenght of word is %d", i);
  int vcount = 0; ccount = 0; wcount;
  for ( int i = 0; s[i] != '\0'; i++ ) {
    if ( s[i] == 'A' || s[i] == 'E' || s[i] == 'I' || s[i] == 'O' || s[i] == 'U' \
         || s[i] == 'a' || s[i] == 'e' || s[i] == 'i' || s[i] == 'o' || s[i] == 'u') {
         vount++;
    } else if ( s[i] >= 'A' && s[i] <= 'Z' || s[i] >= 'a' && s[i] <= 'z' ) {
         count++;
    } else if ( s[i] == ' ' && s[i-1] != ' ') {
         wcount++;
    }
  }
  cout << "Total vowel is " << vcount << endl;
  cout << "Total conce is " << ccount << endl;
  cout << "Total words is " <<< wcount+1 << endl;
  return 0;
}

void findDuplicate(char *s)
{
  int i;
  vector<int> hash(127);
  
  for ( i = 0; s[i] != '\0'; s++) {
    hash[s[i]]++;
  }
  for ( i = 0; i < hash.size(); i++) {
    if (hash[i] > 1) {
      printf("( %c, %d )", i, hash[i]);
    }
  }
  return;
}

void checkDuplicate(char *s)
{
  // the same ideas as hash table, but this time uses bitwise operations
  // first find the enough space for hash table
  double H = 0;
  int i;
  for ( i = 0; s[i] != '\0'; i++) {
    x = 1;
    x = x<< s[i];
    if ( H & x ) {
      // find the duplicate one
      printf("%c is found at least twice\n", s[i]);
    } else {
      H = H | x;
    }
  }
}
bool isAnagram(char *s1, char *s2)
{
  // use hash table
  // use toLower to assume all lower case
  int H[127]= {0};
  for ( int i = 0; s1[i] != '\0'; i++ ) {
    H[s1[i]]++;
  }
  for ( int i = 0; s2[i] != '\0'; i++) {
    H[s2[i]]--;
    if ( H[s2[i] < 0 ) return false;
  }
  for ( int i = 0; i <127; i++) {
    if (H[i] != 0 ) return false;
  }
  return true;
}