Arrays and Strings : Implement an algorithm to determine if a string has all unique characters.

This problem can be easily solved by using a buffer array of the type bool which will act as a check parameter to see if the character already occurred in string or not .

lets start coding :-


#include<iostream.h>
#include<conio.h>
#include<cstring.h>

bool checkUnique(string s)
{
 bool a[256];
 memset(a,0,sizeof(a)) ;
 int len = s.length();
for(int i=0;i<len;i++)
 {
             int pos =  (int)s[i] ;
             if(a[pos]) return false ;
            a[pos] = 1  ;

}
return true ;
}
int main (){
  string s1 = "Hello this is my first post" ;
  string s2 = "qwertyuiopasdfgghjklzxcvbnm" ;
 cout<<checkUnique(s1)<<endl ;
 cout<<checkUnique(s2)<<endl  ; 
 return 0 ;
}

Here what i used is a for loop in which i pick a character convert it into integer (its ascii value) and check at that location what array "a" holds .
if its "1" that means the character is repeated and its not unique otherwise continue the loop .