Write a Console Java program that asks the user to enter one sentence on the keyboard. Output on the console:
1 answer:
Answer:
Here is the JAVA program:
import java.util.Scanner; //to accept input from user
public class Main{ //class name
public static void main(String[] args){ //start of main function
String sentence; //to store the input sentence
int i, length; //declare variables
int count[] = new int[256]; //creates a counter array
Scanner input = new Scanner(System.in); //creates Scanner class object to accept input from user
System.out.println("Enter a sentence: "); //prompts user to enter a sentence
sentence = input.nextLine(); //scans and reads the entire sentence string from user
String[] words = sentence.split("\\s+"); //splits the sentence into an array with separator as one or more white spaces and stores this array in words
System.out.println("Number of words: " + words.length); //display the number of words in sentence by using length which returns the length of the words array
sentence = sentence.toLowerCase(); // converts the sentence into lower case to ignore case sensitivity
sentence = sentence.replaceAll("\\s+",""); //removes the empty spaces from sentence
length = sentence.length(); //stores the length of the sentence string into length variable
for (i = 0; i < length; i++) { //iterates through the length of the sentence
count[(int) sentence.charAt(i)]++; } //counts occurrence of each alphabet in the sentence and stores it in count array
for (i = 0; i < 256; i++) { displays occurrence of alphabet in sentence
if (count[i] != 0) { //if count array is not empty
System.out.println((char) i + "-" + count[i]); }}}}
//prints each alphabet and its count
Explanation:
The program prompts the user to enter a sentence. Suppose the user enters "We won" so
sentence = "We won"
Now this sentence splits into an array with white space as separator and stored in words array. So words array has two words of sentence now i.e. "We" and "won"
Next words.length is used to return the length of words array. So length of words array is 2 hence
number of words = 2
Next the sentence is converted to lower case and spaces are removes so sentence becomes:
wewon
sentence.length() returns the length of sentence which is 5.
Next the for loop is used. At each iteration of this loop occurrence each character of sentence is added to the count[] array. charAt() is used to return a character at each index position of string. So the frequency of every character is counted and stored in count array.
Next is a for loop that is used to display each alphabet in the sentence along with its frequency in alphabetic order.
Hence the entire program gives the output:
Number of words: 2 e-1 n-1 o-1 w-2
The screenshot of the output of example given in the question is attached.
You might be interested in
Answer:
a)
#include<stdio.h>
#include<stdlib.h>
#include<fcntl.h>
#include<unistd.h>
#define BUFSIZE 16
int main(){
//pipe descriptors
char msg[BUFSIZE];
char buf[BUFSIZE];
int pipefd[2];
if(pipe(pipefd) == -1){
//pipe creation error
perror("pipe");
exit(EXIT_FAILURE);
}
//pipe creation successfull
//write four messages
sprintf(msg , "apple");
write(pipefd[1], msg, BUFSIZE);
printf("Written %s\n", msg);
sprintf(msg , "boy");
write(pipefd[1], msg, BUFSIZE);
printf("Written %s\n", msg);
sprintf(msg , "cat");
write(pipefd[1], msg, BUFSIZE);
printf("Written %s\n", msg);
sprintf(msg , "dog");
write(pipefd[1], msg, BUFSIZE);
printf("Written %s\n", msg);
//read
read(pipefd[0], buf, BUFSIZE);
printf("Read: %s\n", buf);
read(pipefd[0], buf, BUFSIZE);
printf("Read: %s\n", buf);
read(pipefd[0], buf, BUFSIZE);
printf("Read: %s\n", buf);
read(pipefd[0], buf, BUFSIZE);
printf("Read: %s\n", buf);
close(pipefd[0]);
close(pipefd[1]);
return 0;
}
(b)
#include<stdio.h>
#include<stdlib.h>
#include<fcntl.h>
#include<unistd.h>
#include<wait.h>
#define BUFSIZE 16
int main(){
//pipe descriptors
char msg[BUFSIZE];
char buf[BUFSIZE];
int pipefd[2];
if(pipe(pipefd) == -1){
//pipe creation error
perror("pipe");
exit(EXIT_FAILURE);
}
//pipe creation successfull
//write four messages
if(fork() == 0){
//this is child
//close unused write end
close(pipefd[1]);
read(pipefd[0], buf, BUFSIZE);
printf("This is child process reading first message. Content is %s\n", buf);
read(pipefd[0], buf, BUFSIZE);
printf("This is child process reading second message. Content is %s\n", buf);
read(pipefd[0], buf, BUFSIZE);
printf("This is child process reading third message. Content is %s\n", buf);
read(pipefd[0], buf, BUFSIZE);
printf("This is child process reading fourth message. Content is %s\n", buf);
close(pipefd[0]);
//exit from child
exit(EXIT_SUCCESS);
}
//this is parent process
//close unused read end
close(pipefd[0]);
sprintf(msg , "apple");
printf("This is parent process. Writing first message into pipe\n");
write(pipefd[1], msg, BUFSIZE);
sprintf(msg , "boy");
printf("This is parent process. Writing second message into pipe\n");
write(pipefd[1], msg, BUFSIZE);
sprintf(msg , "cat");
printf("This is parent process. Writing third message into pipe\n");
write(pipefd[1], msg, BUFSIZE);
sprintf(msg , "dog");
printf("This is parent process. Writing fourth message into pipe\n");
write(pipefd[1], msg, BUFSIZE);
close(pipefd[1]);
//wait for child
wait(NULL);
return 0;
}
(c)
#include<stdio.h>
#include<stdlib.h>
#include<fcntl.h>
#include<unistd.h>
#include<sys/wait.h>
#include<sys/types.h>
#include<signal.h>
typedef struct sigaction Sigaction;
unsigned long long size = 0;
void alarmhandler(int sig){
//alarm fired writing blocked
printf("Write blocked after %llu characters\n", size);
exit(EXIT_SUCCESS);
}
int main(){
//pipe descriptors
int pipefd[2];
if(pipe(pipefd) == -1){
//pipe creation error
perror("pipe");
exit(EXIT_FAILURE);
}
//install handler
sigset_t mask , prev;
sigemptyset(&mask);
sigaddset(&mask , SIGALRM);
sigprocmask(SIG_BLOCK , &mask , &prev);
Sigaction new_action;
sigemptyset(&new_action.sa_mask);
new_action.sa_flags = SA_RESTART;
new_action.sa_handler = alarmhandler;
sigaction(SIGALRM , &new_action , NULL);
sigprocmask(SIG_SETMASK , &prev, NULL);
while(1){
//print size on multiple of 4
if(size != 0 && size % 1024 == 0){
printf("%llu characters in pipe\n", size);
}
//reset previous alarm
alarm(0);
//set new alarm for 5 seconds
alarm(5);
//write to pipe one character
write(pipefd[1], "A", sizeof(char));
size++;
}
return 0;
}
Explanation:
Output for a, b, c are pasted accordingly
