Reverse order of words in string in C

gistfile1.c

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

int main() {
  
  char s[] = "hello world!";
  int n = strlen(s);
  
  // reverse string in-place.
  int i, j, t;
  for(i=0, j=n-1; i<j; ++i, --j) {
    char c = s[i];
    s[i] = s[j];
    s[j] = c;
  }
  
  printf("%s\n", s);
  
  // reverse words, in place.
  for(i=0, j=0; i < n; i=j) {
    while(j < n && s[j] != ' ') j++;
    for(t=j-1; i<t; ++i, --t) {
      char c = s[i];
      s[i] = s[t];
      s[t] = c;
    }
    while(j < n && s[j] == ' ') j++;
  }
    
  printf("%s\n", s);
  
  return 0;
}