Why variable revSentence is still blank?

Question

https://code.sololearn.com/cZkzvEmTRplq/?ref=app

Answer 1

For one, "revSentence" is initially empty, so accessing non-existing characters via the [] operator is undefined behaviour. It should be noted that the [] operator is only meant for accessing characters in the string, you can't add additional characters with it.
Then, you are iterating past the end of the first string in the first loop, which is also undefined behaviour. Since strings are zero-indexed, their length is the first position after the end of the string, and not a valid position itself.
Even taking those out of account, using a nested loop is just going to fill "revSentence" with the last character of the original sentence, since the inner loop sets every character to the current character of the original string, which will be the last character during the final iteration.

Here is a collection of (in-place) string-reversing techniques if you need it:
https://code.sololearn.com/ca110a19a1A2/?ref=app

Edit: Seems you changed the code a bit, so the first point no longer applies.

Answer 2

Shadow Can you please see this one too?
https://code.sololearn.com/ccUdVpc5p4vy/?ref=app

Answer 3

Your character array is uninitialized, adding something to its elements is undefined behaviour. Also, why are you using a nested loop again?

Answer 4

Shadow I'm leaving this code here.. 😂
Thanks Shadow..