Write a program that prints the reverse of a given string.

Program in C

#include <stdio.h>
#include <string.h>

void reverseString(char str[]) {
    int length = strlen(str);

    for (int i = length - 1; i >= 0; i--) {
        printf("%c", str[i]);
    }
    printf("\n");
}

int main() {
    char str[] = "EasyExamNotes";

    printf("Original string: %s\n", str);
    printf("Reversed string: ");
    reverseString(str);

    return 0;
}

Explanation:

• In this program, the reverseString function takes a character array str as a parameter.
• It calculates the length of the string using the strlen function.
• Then, it iterates through the characters of the string in reverse order and prints them one by one.
• Finally, it prints a new line character to complete the reversed string.
• In the main function, a character array str is declared with the example string “EasyExamNotes”.
• The original string is printed to the console, and then the reverseString function is called with the string as the argument.
• The reversed string is printed by the reverseString function.

Output:

Original string: EasyExamNotes
Reversed string: setoNmaxEysaE

Program in Java

public class ReverseString {
    public static void reverseString(String str) {
        int length = str.length();

        for (int i = length - 1; i >= 0; i--) {
            System.out.print(str.charAt(i));
        }
        System.out.println();
    }

    public static void main(String[] args) {
        String str = "EasyExamNotes";

        System.out.println("Original string: " + str);
        System.out.print("Reversed string: ");
        reverseString(str);
    }
}

Explanation:

1. The program defines a public class named ReverseString.
2. Inside the class, the program defines a static method named reverseString that takes a String parameter named str.
3. The length of the string is obtained using the length() method of the String class, and it is stored in the variable length.
4. The method then enters a for loop that iterates from length – 1 (the last character index) down to 0 (the first character index).
5. Inside the loop, the method uses the charAt(i) method of the String class to access the character at the current index i in the string str. This character is printed using System.out.print().
6. After the loop finishes, a newline character is printed using System.out.println() to move the output to the next line.
7. The program also defines a main method, which is the entry point of the program.
8. Inside the main method, a string str is declared and initialized with the value “EasyExamNotes”.
9. The original string is printed to the console using System.out.println().
10. The reverseString method is called with the str string as an argument to reverse the string and print the reversed version.

Original string: EasyExamNotes
Reversed string: setoNmaxEysaE