Java 使用 for 循环打印数组元素
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Printing array elements with a for loop
提问by Anne
This is a challenge question from my online textbook I can only get the numbers to prin forward... :(
这是我在线教科书中的一个挑战问题，我只能得到数字来打印...... :(
Write a for loop to print all elements in courseGrades, following each element with a space (including the last). Print forwards, then backwards. End each loop with a newline. Ex: If courseGrades = {7, 9, 11, 10}, print: 7 9 11 10 10 11 9 7
编写一个 for 循环来打印 courseGrades 中的所有元素，每个元素后面都有一个空格（包括最后一个）。向前打印，然后向后打印。以换行符结束每个循环。例如：如果 courseGrades = {7, 9, 11, 10}，则打印：7 9 11 10 10 11 9 7
Hint: Use two for loops. Second loop starts with i = NUM_VALS - 1.
提示：使用两个 for 循环。第二个循环从 i = NUM_VALS - 1 开始。
Note: These activities may test code with different test values. This activity will perform two tests, the first with a 4-element array (int courseGrades[4]), the second with a 2-element array (int courseGrades[2]).
注意：这些活动可能会使用不同的测试值来测试代码。此活动将执行两个测试，第一个使用 4 元素数组 (int courseGrades[4])，第二个使用 2 元素数组 (int courseGrades[2])。
import java.util.Scanner;
public class CourseGradePrinter {
public static void main (String [] args) {
final int NUM_VALS = 4;
int[] courseGrades = new int[NUM_VALS];
int i = 0;
courseGrades[0] = 7;
courseGrades[1] = 9;
courseGrades[2] = 11;
courseGrades[3] = 10;
/* Your solution goes here */
for(i=0; i<NUM_VALS; i++){
System.out.print(courseGrades[i] + " ");
}
for(i=NUM_VALS -1; i>3; i++){
System.out.print(courseGrades[i]+ " ");
}
return;
}
}
回答by Tim Biegeleisen
Your two loops almost were correct. Try using this code:
你的两个循环几乎是正确的。尝试使用此代码：
for (int i=0; i < NUM_VALS; i++) {
// this if statement avoids printing a trailing space at the end.
if (i > 0) {
System.out.print(" ");
}
System.out.print(courseGrades[i]);
}
for (int i=NUM_VALS-1; i >= 0; i--) {
if (i > 0) {
System.out.print(" ");
}
System.out.print(courseGrades[i] + " ");
}
回答by Joels Elf
To print backwards you want:
要向后打印您想要的：
for(i = NUM_VALS - 1; i >= 0; i--) {
System.out.print(courseGrades[i] + " ");
}
// To end with a newline
System.out.println("");
回答by A. Nony Mous
This is the code to answer the question from zyBooks, 6.2.3: Printing array elements with a for loop.
这是回答 zyBooks 问题的代码，6.2.3：用 for 循环打印数组元素。
for (i = 0; i < NUM_VALS; i++) {
System.out.print(courseGrades[i] + " ");
}
System.out.println("");
for (i = NUM_VALS - 1; i >= 0; i--) {
System.out.print(courseGrades[i] + " ");
}
System.out.println("");
