include<stdio.h>
//#include<conio.h>
#include<string.h>
char input[100];
int i,l;
int main()
{
printf("recursive decent parsing for the grammar");
printf("\n E->TEP|\nEP->+TEP|@|\nT->FTP|\nTP->*FTP|@|\nF->(E)|ID\n");
printf("enter the string to check:");
scanf("%s",input);
if(E()){
if(input[i]=='$')
printf("\n string is accepted\n");
else
printf("\n string is not accepted\n");
}
}
E(){
if(T()){
if(EP())
return(1);
else
return(0);
}
else
return(0);
}
EP(){
if(input[i]=='+'){
i++;
if(T()){
if(EP())
return(1);
else
return(0);
}
else
return(1); }}
T(){
if(F()){
if(TP())
return(1);
else
return(0); }
else
return(0);
printf("String is not accpeted\n");
}
TP(){
if(input[i]=='*'){
i++;
if(F()){
if(TP())
return(1)
;
else
return(0); }
else
return(0);
printf("The string is not accepted \n");
}
else
return(1); }
F(){
if(input[i]=='('){
i++;
if(E()){
if(input[i]==')'){
i++;
return(1); }
else
{
return(0);
printf("String is not accepted\n");
}
}
else
return(0);
}
else
if(input[i]>='a'&&input[i]<='z'||input[i]>='A'&&input[i]<='Z')
{
i++;
return(1);
}
else
return(0);
} OUTPUT:
$ cc rdp.c
$ ./a.out
recursive decent parsing for the grammar
E->TEP|
EP->+TEP|@|
T->FTP|
TP->*FTP|@|
F->(E)|ID
enter the string to check:(i+i)*i
string is accepted
