#include<stdio.h>
#include<stdlib.h>
#define max 50
typedef struct stack
{
char ar[max];
int top;
}st;
void push(st *,char);
char pop(st *);
char peek(st);
char getmatchsymbol(char);
int isfull(st);
int isempty(st);
int parenthesischeck(char []);
void main()
{
//int ch,g;
char equation[100];
printf("Enter the equation : ");
fgets(equation,100,stdin);
if(parenthesischeck(equation))
printf("Parenthesis are OK");
else
printf("Parenthesis are not OK");
}
void push(st *s,char g)
{
s->ar[++s->top]=g;
}
char pop(st *s)
{
int p;
p=s->ar[s->top];
s->top--;
return p;
}
char peek(st s)
{
return s.ar[s.top];
}
int isfull(st s)
{
if(s.top==max-1)
return 1;
else
return 0;
}
int isempty(st s)
{
if(s.top==-1)
return 1;
else
return 0;
}
char getmatchsymbol(char ch)
{
switch(ch)
{
case '(': return ')';
case '{': return '}';
case '[': return ']';
case ')': return '(';
case '}': return '{';
case ']': return '[';
}
}
int parenthesischeck(char equ[])
{
int i;
st s;
s.top=-1;
for(i=0;equ[i];i++)
{
if(equ[i]=='{' || equ[i]=='(' || equ[i]=='[')
push(&s,equ[i]);
else if(equ[i]=='}' || equ[i]==')' || equ[i]==']')
{
if(peek(s) == getmatchsymbol(equ[i]))
pop(&s);
else
return 0;
}
}
if(!isempty(s))
return 0;
else
return 1;
}
