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A. A postfix expression of the formab+cd-*ab/ is to be evaluated
after accepting the values of a, b, c and d. The value should be accepted only once and the same value is to be used for repeated occurrence of same symbol in the expression. Formulate the problem and write a C program to solve the problem by using stack Ans: #include<stdio.h> #define MAXSIZE 50 typedef struct stack { int data[MAXSIZE]; int top; }STACK; void initstack(STACK *ps) { ps->top=-1; } void push(STACK *ps,int num) { ps->top++; ps->data[ps->top]=num; } int pop(STACK *ps) { int num; num=ps->data[ps->top]; ps->top--; return num; } int peek(STACK *ps) { return ps->data[ps->top]; }
int IsEmpty(STACK *ps) { if(ps->top==-1) return 1; else return 0; } int IsFull(STACK ps) { if(ps->top==MAXSIZE-1) return 1; else return 0; } #include<stdio.h> #include "stack.h" #include<math.h> int evaluate(char postfix[20]) { STACK s; int value,i,opnd1,opnd2; initstack(&s); for(i=0;postfix[i]!='\0';i++) { switch(postfix[i]) { case '+':opnd2=pop(&s); opnd1=pop(&s); push(&s,opnd1+opnd2); break; case '-':opnd2=pop(&s); opnd1=pop(&s); push(&s,opnd1-opnd2); break; case '':opnd2=pop(&s);
Output:
B. Write a program that adds two single variablepolynomials.
Each polynomial should be represented as a list with
linked list implementation.
Ans: #include<stdio.h> #include<stdlib.h> #define POLY1 (POLY *)malloc(sizeof(POLY)) typedef struct node { int coef,exp; struct node *next; }POLY; void create(POLY *head) { POLY temp=head,newnode; int i,n; printf("\n how many nodes"); scanf("%d",&n); printf("enter the terms in descending order of power"); for(i=1;i<=n;i++) { newnode=POLY1; newnode->next=NULL; printf("\nEnter coeff and exponent"); scanf("%d%d",&newnode->coef,&newnode->exp); temp->next=newnode; temp=newnode; }
newnode->exp=t1->exp; newnode->coef=t1->coef+t2->coef; t1=t1->next; t2=t2->next; } t3->next=newnode; t3=newnode; } while(t1) { newnode=POLY1; newnode->next=NULL; newnode->exp=t1->exp; newnode->coef=t1->coef; t3->next=newnode; t3=newnode; t1=t1->next; } while(t2) { newnode=POLY1; newnode->next=NULL; newnode->exp=t2->exp; newnode->coef=t2->coef; t3->next=newnode; t3=newnode; t2=t2->next; } } void main() { POLY p1,p2,*p3; p1=POLY1;
p1->next=NULL; p2=POLY1; p2->next=NULL; p3=POLY1; p3->next=NULL; create(p1); display(p1); create(p2); display(p2); add(p1,p2,p3); printf("\n addition is"); display(p3); }
