CLASS NOTES FOR 9/17/02
Stack 

Queue 

Tree

Graph

Searching 

Sorting

 

1)   Which of the following program is better?

a)

cout<<ĦħEnter Your NameĦħ; char name [15]

cin>>name; int age

cin>> age; float salary

 

OR
 

b)

cout<<ĦħEnter your NameĦħ;                                struct person

cin>>employee.name;                                         {

cin>>employee.age;                                            char name [15]

                                                                                int age

float salary

}

person employee

 

 

Choice b is a better form of programming because it has structure to it.

 

Infix Evaluation
2 3 4 * +

Algorithm = If digit then PUSH

                                else

                                if operator 

                                pop 

                                pop

                                evaluate

                                push

                                else no more, pop

                                DISPLAY

 

How would make a stack?
Array
176 786 664 

 

0 1 2 3

 

Stack
number [0] = 176

number [1] = 786

number [2] = 664

number [i] 

                i++;

stack [i]

                i++;

 

change i to top

 

stack[top] = X

top++;

 

1)       Write a function called Push?

Int stack [10];

Int top = 0;

Int x;

Push (){

Stack [top] = x

Top++;

}

main()

{

push();

}//main

 

2)       2 ways to use stack are Array and Pointer

SIMPLE STACK MENU
 

#include<iostream.h>

void push (int mystack[],int & mytop,int item){

        mystack[mytop]=item;

        mytop=mytop+1;} //PUSH

int pop(int mystack[],int &mytop){

        mytop=mytop-1;

        int item=mystack[mytop];

        return item; }//POP

int isempty(int mytop){

        if(mytop==0) return 1;

        else return 0;}//ISEMPTY

int isfull(int mytop,const int MAXSTACKSIZE){

        if(mytop==MAXSTACKSIZE)return 1;

        else return 0;}//ISFULL

void main(){

        const int MAXSTACKSIZE=5;

        int mystack[MAXSTACKSIZE];int mytop,x,option;

        mytop=0;//STACK TOP INITILIZATION

        do{cout<<"SELECT ONE OF THE FOLLOWING OPTIONS:"<<endl;

        cout<<"1-PUSH 2-POP 3-EMPTY 4-ISFULL 5-QUIT:";

        cin>>option;

        switch(option){

        case 1: if (isfull(mytop,MAXSTACKSIZE))

                                                        cout<<"YOU CANT PUSH"<<endl;

                        else{ cout<<"ENTER THE NUMBER THAT WILL BE PUSHED:";

                                                        cin>>x;

                                                        push(mystack,mytop,x);}//ELSE

                        break;

        case 2: if(isempty(mytop))

                                                        cout<<"YOU CANT POP"<<endl;

                        else{ cout<<"THE NUMBER POOPED IS:"<<pop(mystack,mytop);

                        cout<<endl;}//ELSE

                        break;

        case 3: if(isempty(mytop)==1)

                                                        cout<<"STACK EMPTY."<<endl;

                        else cout<<"STACK IS NOT EMPTY."<<endl;

                        break;

        case 4: if(isfull(mytop, MAXSTACKSIZE)==1)

                                                                        cout<<"STACK FULL."<<endl;

                        else cout<<"STACK IS NOT FULL."<<endl;

                        break;

        case 5: cout<<"THANK YOU FOR USING OUR MENU!"<<endl;

                        break;

        default:cout <<"ENTER CORRECT OPTIONS"<<endl;}//switch

        }while (option !=5);

}//MAIN