Can you think of a better way to solve the problem of string inversion?

At the weekend, a friend asked a written test question , At that time, I wrote the answer live , But I always feel that my writing is not good enough , Now let's put the topic out . Let's see if there is a better solution

subject

There's a string , as follows , Require the string to be inverted and output

//input  the sky is blue

//output blue is sky the

My answer is like the following code , I directly define it as an array to operate , If it's defined as char * str   Words , Do you have any ideas ？

#include "stdio.h"char input[] = {"the sky is blue"};// subject ://input  the sky is blue//output blue is sky thevoid reverseWords(char* s, int n) {	char ch;
	int i=0;
	for (i=0; i<n/2; i++) {
		ch = s[i];
		s[i] = s[n-i-1];
		s[n-i-1] = ch;
	}}//eulb si yks ehtvoid reverseWords_by_space(char* s, int n) {	int i = 0;
	int len = 0;
	for (i=0; i<n; i++) {
		if (s[i] == ' ') {
			reverseWords(s+i-len, len);
			len = 0;
		} else if (s[i] == '\0') {
			reverseWords(s+i-len, len);
			len = 0;			
		}
		if (s[i] != ' ') {
			++len;
		}
	}}int main(void) {	printf("%s\n", input);
	reverseWords(input,strlen(input));
	reverseWords_by_space(input,sizeof(input));
	printf("%s\n", input);
	//  Finished writing , If you have any comments you don't understand 
	return 0;}