source code

#include
#include
#include
#include
#include
#include
void main()
{
clrscr();
fflush(stdin);
char b[8][7][4],s[10],str[30],e[20];
int i,j,k,l,t,g,t1,t2;
for(i=0;i<10;i++)
s[i]='\0';
s[10]='\0';
cout<<"\t Input string\n\n";
cin>>str;
/*cout<<"\t Input table\n\n";
for(i=0;i<6;i++)
for(j=0;j<7;j++)
cin>>b[i][j];*/
strcpy(b[0][0]," ");
strcpy(b[0][1],"a");
strcpy(b[0][2],"+");
strcpy(b[0][3],"*");
strcpy(b[0][4],"(");
strcpy(b[0][5],")");
strcpy(b[0][6],"$");
strcpy(b[1][0],"E");
strcpy(b[1][1],"TW");
strcpy(b[1][2],"q");
strcpy(b[1][3],"q");
strcpy(b[1][4],"TW");
strcpy(b[1][5],"q");
strcpy(b[1][6],"q");
strcpy(b[2][0],"W");
strcpy(b[2][1],"q");
strcpy(b[2][2],"+TW");
strcpy(b[2][3],"q");
strcpy(b[2][4],"q");
strcpy(b[2][5],"@");
strcpy(b[2][6],"@");
strcpy(b[3][0],"T");
strcpy(b[3][1],"FR");
strcpy(b[3][2],"q");
strcpy(b[3][3],"q");
strcpy(b[3][4],"FR");
strcpy(b[3][5],"q");
strcpy(b[3][6],"q");
strcpy(b[4][0],"R");
strcpy(b[4][1],"q");
strcpy(b[4][2],"@");
strcpy(b[4][3],"*FR");
strcpy(b[4][4],"q");
strcpy(b[4][5],"@");
strcpy(b[4][6],"@");
strcpy(b[5][0],"F");
strcpy(b[5][1],"a");
strcpy(b[5][2],"q");
strcpy(b[5][3],"q");
strcpy(b[5][4],"(E)");
strcpy(b[5][5],"q");
strcpy(b[5][6],"q");
cout<<"\n parser table \n";
for(i=0;i<6;i++)
{
for(j=0;j<7;j++)
cout<cout<}
cout<s[0]='$';
s[1]='E';
t=1;
l=0;
cout<<"STACK\t INPUT\t\tACTION\n";
while((l{
for(t1=0;t1cout<cout<<"\t";
for(t1=1;t1cout<if(s[t]==str[l])
{
t--;
l++;
continue;
}
for(i=0;i<6;i++)
if(s[t]==b[i][0][0])
{
t1=i;
break;
}
for(j=0;j<7;j++)
if(str[l]==b[0][j][0])
{
t2=j;
break;
}
strcpy(e,b[t1][t2]);
cout<<"\t\t"<"<if(strcmp(e,"q")==0)
{
cout<<"syntax error\n press any key to exit";
exit(0);
}
strrev(e);
for(int f=0;fs[t]=e[f];
t--;
if(s[t]==str[l])
{
t--;
l++;
}
else
{
if(s[t]=='@')
t--;
}
}
if((s[t]=='$')&&(str[l]=='$'))
cout<else
cout<<"syntax error";
getch();
}





Output:

Input string: a+a$
Parser table:
a + * ( ) $

E TW q q TW q q

W q +TW q q @ @

T FR q q FR q q

R q @ *FR q @ @

F a q q (E) q q


Stack Input Action
$E a+a$ E->TW
$WT a+a$ T->FR
$WRF a+a$ F->a
$WR +a$ R->@
$W +a$ W->+TW
$WT a$ T->FR
$WRF a$ F->a
$WR $ R->@
$W $ W->@

a+a$ string is syntactically correct & it is accepted