Reverse The Words In A String | C Programming Example

An example of how to reverse the words in a string with C. Source code: github.com/por.... Check out www.portfolioc... to build a portfolio that will impress employers!

[@durkaperiasamy2405]

Im from India i found ur video's very late...boz semester (final)exams are near but after final i promise i will complete ur c programming playlist....❤🎉😊

[@Dhana2100]

Did You?

[@ManikantaSaiTejaMathi]

Nice set of programs

[@warplanner8852]

Use strtok() to strcpy() words into an array of strings. Then traverse the array in reverse order. Advantage: easier to implement. (Specious advantage). Disadvantage: cannot process an infinite string.

[@mohamedelamine1640]

hey sir ! sorry if it is dumb question but i'm new to programming , so when you said we gonna check whether we reached
the end of the string or not , what if the string doesn't end with a space or dot , so the last word in string will not be detected per eg: "good morning sir" so the word "sir" will not be detected unless the string is like that "good morning sir." or that "good morning sir "

[@PortfolioCourses]

That's a great question Mohamed. So it will also stop when we reach the end of the string itself. If you look at the source code here: github.com/portfoliocourses/c-example-code/blob/main/reverse_words.c. Specifically, this part here:
for (j = 0; i < len; j++, i++)
{
if (s[i] == ' ' || s[i] == '.')
break;
temp[j] = s[i];
}
the for loop will stop if s[i] is a period or space, but it will *also* stop if i >= len, as the loop will only continue so long as i < len. And we keep incrementing i in the for loop each time, and we keep writing the word into 'temp'. So it should work fine for the last word whether we have "good morning sir." or "good morning sir".

[@mohamedelamine1640]

@@PortfolioCourses Thank you so much 👌😁

[@PortfolioCourses]

@@mohamedelamine1640 You're welcome Mohamed! :-D

[@madhubabu3482]

The occurences or frequency of words in a string. Please do it.

[@PortfolioCourses]

Is this video what you're looking for Madhu? :-) Video: th-cam.com/video/Zydf9p1VOGU/w-d-xo.html

[@Awesomeman1578]

What if there is more than one whitespace between every new word?

[@PortfolioCourses]

If there is a white space character, the inner for loop will immediately break here:
if (s[i] == ' ' || s[i] == '.')
break;
And then the inner while loop will do nothing, and the outer for loop will advance i by 1. The process will just repeat until we hit the next non-space character, so it should work fine in this case.

[@justcurious1940]

Great method :
// an alternative method without using a temporary array
// by keeping track of the first and the last index for each word
void reverse_words3(char *string){
bool is_word = false;
int first_index = 0, last_index = 0;
for(int i = 0; string[i]; i++){
if(string[i] != ' ' && string[i] != '.'){
if(!is_word){
first_index = i;
is_word = true;
}
}
else if ((string[i] == ' ' || string[i] == '.')){
if(is_word){
last_index = i-1;
is_word = false;
while(first_index < last_index){
char temp = string[first_index];
string[first_index] = string[last_index];
string[last_index] = temp;
++first_index;
--last_index;
}
}
}
}
}

[@mostafamoradi2051]

it could be better if the reverse function which has been defined could reverse the place of the words too.... i mean like : yaw eht si siht... anyway. that was good. tnx

[@PortfolioCourses]

So reverse the entire string? I bet that I can make a video on that too, I'll let you know when I post it. :-D
In the meantime I have this video where a string is printed in reverse: th-cam.com/video/iWQ5rGWmkXw/w-d-xo.html

[@PortfolioCourses]

OK, here is a video for creating a function that will reverse the entire string: th-cam.com/video/PtSHcou0WIs/w-d-xo.html