PS: Self-written, self-tested OK for your reference.
/*
* Enter an expression (3*8 + 7-2) with no parentheses to output the result.
*/
/* This program does not consider fault tolerance Processing for the moment */
1 import java. util. iterator; 2 3 public class Calculator {4 5/* For example, in expression 3*8 + 7-2, dataNum = 4, opNum = 3 */6 private static int daNum = 0; // number of data in the expression 7 private static int opNum = 0; // number of operators in the expression 8 9 public static void main (String [] args) {10 11 System. out. println ("enter an arithmetic expression (for example, 3*8 + 7-2):"); 12 seconds s = new seconds (System. in); 13 // String str = s. nextLine (). toString (); 14 char [] ch = s. nextLine (). toChar Array (); 15 s. close (); 16 StringBuffer sbOP = new StringBuffer (); 17 StringBuffer sbDA = new StringBuffer (); 18 19 int dataIndex = 0; 20 int [] data = new int [32]; // limits the maximum number of data to be processed to 32 21 22 for (int I = 0; I <ch. length; I ++) 23 {24 if ('+' = ch [I]) | ('-' = ch [I]) | ('*' = ch [I]) | ('/' = ch [I]) 25 {26 sbOP. append (ch [I]); 27 opNum ++; 28 for (int j = dataIndex; j <I; j ++) 29 {30 sbDA. append (ch [j ]); 31} 32 data [daNum ++] = Integer. parseInt (sbDA. toString (); 33 sbDA. delete (0, sbDA. length (); // clear sbDA 34 dataIndex = I + 1; 35} 36} 37 for (int j = dataIndex; j <ch. length; j ++) 38 {39 sbDA. append (ch [j]); 40} 41 data [daNum ++] = Integer. parseInt (sbDA. toString (); 42 int [] da = new int [daNum]; // numeric array 43 for (int I = 0; I <daNum; I ++) 44 {45 da [I] = data [I]; 46 // System. out. println ("da:" + da [I] ); 47} 48 char [] op = sbOP. toString (). toCharArray (); // operator array 49 50 System. out. println ("=" + cal (da, op); 51} 52 53 private static int cal (int [] da, char [] op) {54 55 if (1 = daNum) 56 {57 return da [0]; 58} 59 60 // indicates the initialization, so the da value is valid 61 boolean [] flag = new boolean [daNum]; 62 for (int I = 0; I <daNum; I ++) 63 {64 flag [I] = true; 65} 66 67 while (1! = DaNum) 68 {69 // multiplication and division operation 70 for (int I = 0; I <opNum; I ++) 71 {72 if ('*' = op [I]) 73 {74 da [I + 1] = da [I] * da [I + 1]; 75 flag [I] = false; 76 daNum --; 77} 78 if ('/' = op [I]) 79 {80 da [I + 1] = da [I]/da [I + 1]; 81 flag [I] = false; 82 daNum --; 83} 84} 85 86 // addition/subtraction operation 87 int index = 0; 88 for (int I = 0; I <opNum; I ++) 89 {90 index = I + 1; 91 if ('+' = op [I]) 92 {93 while (! Flag [index]) 94 {95 index ++; 96} 97 da [index] = da [I] + da [index]; 98 flag [I] = false; 99 daNum --; 100} 101 if ('-' = op [I]) 102 {103 while (! Flag [index]) 104 {105 index ++; 106} 107 da [index] = da [I]-da [index]; 108 flag [I] = false; 109 daNum --; 110} 111} 112} 113 114 return da [opNum]; 115} 116}
JAVA machine testing questions
Question 1:
Import java. util. ArrayList;
Import java. util. List;
Class Vehicle {
Public void run (){
System. out. println ("this is the run method of the vehicle ");
}
}
Class Motor extends Vehicle {
Public void run (){
System. out. println ("this is the Motorrun method ");
}
}
Class Ship extends Vehicle {
Public void run (){
System. out. println ("this is the Shiprun method ");
}
}
Class Aeroplane extends Vehicle {
Public void run (){
System. out. println ("this is the Aeroplanerun method ");
}
}
Class Car extends Motor {
Public void run (){
System. out. println ("this is the Carrun method ");
}
}
Class Bus extends Motor {
Public void run (){
System. out. println ("this is the Busrun method ");
}
}
Public class Test {
Public static void main (String [] args ){
List <Vehicle> list = new ArrayList <Vehicle> ();
Vehicle v1 = new Vehicle ();
Vehicle v2 = new Motor ();
Vehicle v3 = new Ship ();
Vehicle v4 = new Aeroplane ();
Vehicle v5 = new Car ();
Vehicle v6 = new Bus ();
List. add (v1 );
List. add (v2 );
List. add (v3 );
List. add (v4 );
List. add (v5 );
List. add (v6 );
For (Vehicle vehicle: list ){
Vehicle. run ();
}
}
}
Java second-level computer test questions compilation and answers
Sweat, speechless, java is useless, and the most important thing is ability. I suggest you study hard and do not give any answers. It hurts yourself.