Java auto-addition and auto-subtraction, java

Java auto-addition and auto-subtraction, java

 1 public class Add { 2  3     public static void main(String[] args) { 4         int i = 0; 5         i=i++ + ++i; 6         int j = 0; 7         j= ++j + j++ + j++ + j++; 8         int k = 0; 9         k=k++ + k++ + k++ + ++k;10         int h = 0;11         h=++h + ++h;12         int p1=0,p2=0;13         int q1=0,q2=0;14         q1=+p1;15         q2=p2++;16         System.out.println("i "+i);17         System.out.println("j "+j);18         System.out.println("k "+k);19         System.out.println("h "+h);20         System.out.println("p1 "+p1);21         System.out.println("p2 "+p2);22         System.out.println("q1 "+q1);23         System.out.println("q2 "+q2);24 25     }26 27 }

Output

i 2j 7k 7h 3p1 0p2 1q1 1q2 0

Resolution: The difference between I ++ and I is that one is the auto-increment after the program is completed, and the other is the auto-increment before the program starts.

The "I = I ++ I" Execution Process is to execute I ++ first, but the I auto-increment 1 operation is executed only later, so I is still 0, then execute ++ I. After ++ I, the value of I is 1. After ++ I is executed, add I ++, so now the I value is actually 2, 0 + 2 = 2, and then assigned to I, the final I value is 2.

"J = ++ j + j ++", the execution process is first ++ j, so the value of j is 1, after j ++ is executed, the value of j after j ++ is still 1, and then j ++ is executed. The execution result is still 1, however, to add the j ++ just now, the actual value of j is 2, and then the last j ++ is executed. The result after execution is still 2, however, we need to add the j ++ just now, so the j value is actually 3, so 1 + 1 + 2 + 3 = 7, and then assign the value to j, the final value of j is 7.

The execution process of "k = k ++" is k ++, so the value of k is 0, then, after k ++ is executed, the value of k after k ++ is still 0, but the value of k must be supplemented with k ++. Therefore, the value of k is actually 1, then execute the last k ++, And the execution result is still 1, but we need to add the k ++ just now, so the value of K is actually 2, the final execution is + + k, and the execution result is 3. Then add k ++. the actual result of k is 4, so 0 + 1 + 2 + 4 = 7, then assign the value to k, and the final value of k is 7.

"H = ++ h" is the first Auto-increment h, the h value is 1, and then the auto-increment is good, the h value is 2, so 1 + 2 = 3, then assign the value to h. The final value of h is 3.

"Q1 = ++ p1" first increments p1. The value of p1 is 1, and then is assigned to q1. Therefore, the value of q1 is 1.

"Q2 = p2 ++" first assigns p2 to q2. The q2 value is 0, and then auto-incrementing p2. Therefore, the p2 value is 1.