如果字符串中还没有空格，如何在其中添加空格？

string = "Thisisateststring"
spaced_string = " ".join(string)
print(spaced_string)

T h i s i s a t e s t s t r i n g

import re

string = "Thisisateststring"
spaced_string = re.sub(r"(.)", r"\1 ", string)
print(spaced_string)

T h i s i s a t e s t s t r i n g

string = "Thisisateststring"
spaced_string = " ".join([string[i:i+1] for i in range(0, len(string))])
print(spaced_string)

T h i s i s a t e s t s t r i n g

#include <stdio.h>
#include <string.h>

int main() {
   char string[] = "Thisisateststring";
   int length = strlen(string);
   
   for (int i = 0; i < length; i++) {
      printf("%c ", string[i]);
   }
   
   return 0;
}

T h i s i s a t e s t s t r i n g