Learn Java-6 from scratch. Execute operations repeatedly using loops and learn java-6
1. Use the for loop;
2. Use the while loop;
3. Use the do-while loop;
4. Early exit loop (break, continue );
5. Name the loop.
Program Nines: display the product of integers 1-and 9
1 package com.jsample; 2 3 public class Nines { 4 public static void main(String[] args){ 5 for(int dex = 1;dex <= 200; dex++){ 6 int multiple = 9 * dex; 7 System.out.println(multiple + " "); 8 } 9 System.out.println();10 }11 }
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Output:
9
......
1800
Program Benchmark: view the number of times the computer calculates the square root in one minute
1 package com. jsample; 2 3 public class Benchmark {// declare Benchmark class 4 public static void main (String [] args) {// start the main () block of the program 5 long startTime = System. currentTimeMillis (); // create the variable startTime, and assign the initial value 6 long endTime = startTime + 60000 to the variable with the current time (millisecond value); // create the endTime variable, exactly one minute before startTime. 7 long index = 0; // create the loop variable index 8 while (true) {// infinite loop. You can only use break to break 9 double x = Math. sqrt (index); // calculates the square root of the index and stores it in the x variable 10 long now = System. currentTimeMillis (); // create the variable now and assign the current time to it 11 if (now> endTime) {// more than one minute, jump out of the loop 12 break; 13} 14 index ++; // auto-increment loop variable 15} 16 System. out. println (index + "loops in one minute. "); // display the number of times the square root is calculated 17} 18}
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Output:
12880432183 loops in one minute.
Program Mod13: Find the first 400 divisible by 13
1 package com.jsample; 2 3 public class Mod13 { 4 public static void main(String[] args){ 5 int index = 0; 6 for(int flag = 1; flag <= 400; index++){ 7 if(index % 13 == 0) { 8 flag++; 9 System.out.println(index + " ");10 }11 }12 }13 }
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Output:
0
......
5187