C Program To Reverse Words In A Given String

// C program to reverse a string
#include <stdio.h>

// Function to reverse any sequence
// starting with pointer begin and
// ending with pointer end
void reverse(char* begin,char* end)
{
    char temp;
    while (begin < end) 
    {
        temp = *begin;
        *begin++ = *end;
        *end-- = temp;
    }
}

// Function to reverse words
void reverseWords(char* s)
{
    char* word_begin = s;

    // Word boundary
    char* temp = s;

    // Reversing individual words as
    // explained in the first step
    while (*temp) 
    {
        temp++;
        if (*temp =='\0') 
        {
            reverse(word_begin,temp - 1);
        }
        else if (*temp == ' ') 
        {
            reverse(word_begin,temp - 1);
            word_begin = temp + 1;
        }
    }

    // Reverse the entire string
    reverse(s, temp - 1);
}

// Driver Code
int main()
{
    char s[] = 
    "i like this program very much";
    char* temp = s;
    reverseWords(s);
    printf("%s", s);
    return 0;
}

// C program to implement
// the above approach
void reverseWords(char* s)
{
    char* word_begin = NULL;
  
    // temp is for word boundary 
    char* temp = s;

    // STEP 1 of the above algorithm
    while (*temp) 
    {
        /*This condition is to make sure 
          that the string start with valid 
          character (not space) only*/
        if ((word_begin == NULL) && 
            (*temp != ' ')) 
        {
            word_begin = temp;
        }
        if (word_begin && 
           ((*(temp + 1) == ' ') ||
            (*(temp + 1) == ''))) 
        {
            reverse(word_begin, temp);
            word_begin = NULL;
        }
        temp++;
    // End of while 
    } 

    // STEP 2 of the above algorithm 
    reverse(s, temp - 1);
}