Chapter 4Java Tutorial~1 min read
Input & Output
Input/Output — Scanner आणि println
Java मध्ये output साठी System.out.println() आणि input साठी Scanner class वापरतात. Scanner java.util package मध्ये आहे — import करावे लागते.
Output — System.out
println, print, printf
java
public class Output {
public static void main(String[] args) {
// println — newline सोबत print
System.out.println("नमस्कार!");
System.out.println("Hello World");
// print — newline नाही
System.out.print("Hello ");
System.out.print("World\n"); // manually newline
// printf — formatted output (C style)
String name = "Rahul";
int age = 20;
double marks = 87.5;
System.out.printf("Name: %s, Age: %d, Marks: %.2f%n",
name, age, marks);
// Name: Rahul, Age: 20, Marks: 87.50
// String concatenation
System.out.println("Name: " + name + ", Age: " + age);
// String.format
String msg = String.format("Hello %s! You scored %.1f%%", name, marks);
System.out.println(msg);
}
}Input — Scanner Class
Scanner — user कडून input घेणे
java
import java.util.Scanner; // import mandatory!
public class UserInput {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
// String input
System.out.print("तुमचे नाव टाका: ");
String name = sc.nextLine(); // पूर्ण line — spaces सोबत
// Integer input
System.out.print("तुमचे वय टाका: ");
int age = sc.nextInt();
// Double input
System.out.print("Marks टाका: ");
double marks = sc.nextDouble();
// Output
System.out.println("\nनमस्कार " + name + "!");
System.out.println("वय: " + age);
System.out.printf("Marks: %.2f%n", marks);
sc.close(); // Scanner बंद करणे — best practice
}
}📌
sc.nextInt() नंतर sc.nextLine() call केल्यास empty string मिळते! nextInt() newline consume करत नाही. Fix: nextInt() नंतर sc.nextLine() एकदा extra call करा (buffer clear करायला).
✅ Key Points — लक्षात ठेवा
- ▸import java.util.Scanner; — file च्या सुरुवातीला
- ▸Scanner sc = new Scanner(System.in) — keyboard input साठी
- ▸nextLine() — full line, next() — word, nextInt(), nextDouble()
- ▸System.out.printf("%s %d %.2f", str, i, d) — formatted
- ▸sc.close() — Scanner बंद करणे good practice
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