String reversal using indexing: what does this C program output after reading a line with gets and then printing characters in reverse order? #include<stdio.h> #include<string.h> int main() { char sentence[80]; int i; printf("Enter a line of text "); gets(sentence); for (i = strlen(sentence) - 1; i >= 0; i--) putchar(sentence[i]); return 0; } Identify the correct behavior.

Introduction / Context:
This question verifies knowledge of iterating backwards through a C string using strlen and array indexing. The code demonstrates reversal by printing characters from the last index down to zero.

Given Data / Assumptions:

• sentence has space for up to 79 visible characters plus the null terminator.
• gets is used (unsafe) to read a line; it excludes the newline and appends '\0' at the end.
• strlen(sentence) returns the number of characters before the null terminator.
• putchar writes single characters in the loop.

Concept / Approach:
The loop initializes i to strlen(sentence) - 1 (the last valid character index) and decrements down to 0 inclusive. This prints the string in reverse order.

Step-by-Step Solution:
User enters text, e.g., "hello".strlen("hello") = 5, so start i = 4.putchar(sentence[4]) prints 'o', then i becomes 3 → prints 'l', then 2 → 'l', then 1 → 'e', then 0 → 'h'.Loop ends after i becomes -1, and the output is the reverse of the input.

Verification / Alternative check:
Compare with using strrev (non-standard) or manual two-pointer reversal in a buffer; all produce the reversed text.

Why Other Options Are Wrong:
Same order: would require forward iteration.Half printed: the loop clearly covers all indices down to 0.None of above / does not compile: the code compiles; logical behavior is reversal.

Common Pitfalls:
Using gets (unsafe, buffer overflow risk); forgetting that strlen excludes the null terminator; off-by-one errors in start or end indices.

Final Answer:
The sentence will get printed in reverse order