Remove spaces from string

A simpler but less efficient solution can be thought of as rearranging the characters everytime we encounter a space (O(n^2)).
But we move to a better solution which can solve it in O(n) time.
The idea is to keep track of count of non-space character seen so far.

1) Initialize 'count' = 0 (Count of non-space character seen so far)
2) Iterate through all characters of given string, do following
     a) If current character is non-space, then put this character
        at index 'count' and increment 'count'
3) Finally, put '\0' at index 'count'

#include <iostream> 
using namespace std; 
  
// Function to remove all spaces from a given string 
void removeSpaces(char *str) 
{ 
    // To keep track of non-space character count 
    int count = 0; 
  
    // Traverse the given string. If current character 
    // is not space, then place it at index 'count++' 
    for (int i = 0; str[i]; i++) 
        if (str[i] != ' ') 
            str[count++] = str[i]; // here count is 
                                   // incremented 
    str[count] = '\0'; 
} 
  
// Driver program to test above function 
int main() 
{ 
    char str[] = "h  ello   there he  llo  "; 
    removeSpaces(str); 
    cout << str; 
    return 0; 
} 

Output:
hellotherehello