Page 557 - Computer science 868 Class 12
P. 557
17. Convert the following infix expression to postfix form: [ISC 2017]
P * Q/R + (S + T)
Ans. P * Q/R + (S + T)
= PQ* / R + (S + T)
= PQ*R / + (S + T)
= PQ*R/ (S+T) +
= PQ*R / ST ++
18. A queue is an entity which can hold a maximum of 100 integers. The queue enables the user to add integers from the rear and
remove integers from the front. [ISC 2017]
Define a class Queue with the following details:
Class name : Queue
Data Members/Instance variables
Que[] : array to hold the integer elements
size : stores the size of the array
front : to point the index of the front
rear : to point the index of the rear
Member Functions
Queue(int mm) : constructor to initialize the data
size = mm, front = 0, rear = 0
void addele(int v) : to add integer from the rear if possible else display the message “Overflow”
int delele() : returns elements from front if present, otherwise displays the message
“Underflow” and return-9999
void display() : displays the array elements
Specify the class Queue giving details of ONLY the functions void addele(int) and int delete()
Assume that the other functions have been defined.
The main function and algorithm need NOT be written.
Ans. public class Queue {
int Quen = new int[100];
int max, f, r;
public class Queue {
int Quen = new int[100];
int max, f, r;
void addele(int v) if (r < max - 1)
Que[+ - Fr]
= v;
else System.out.println("Overflow");
}
int delete()
if (f != r)
return Que[++f];
else
return -9999;
}
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Data Structures 555

