LL1-Parsing.cpp

#include<stdio.h> 
#include<string.h>
#include <process.h> 
char s[20], stack [20];
int main() 
{
	char m[5][6][4]={"tb"," "," ","tb"," "," "," ","+tb"," "," ","n","n","fc"," "," ","fc"," "," "," ","n","*fc"," a", "n", "n","i", " "," ","(e)"," "," "}; 
	int size [5][6]= {2,0,0,2,0,0,0,3,0,0,1,1,2,0,0,2,0,0,0,1,3,0,1,1,1,0,0,3,0,0};
	int i,j,k,n, str1, str2;
	printf("\n Enter the input string: ");
	scanf("%s", s); 
	strcat (s, "$");
	n=strlen(s);
	stack[0]='$';
	stack [1]='e';
	i=1;
	j=0;
	printf("\nStack        Input\n");
	printf("________________________\n");
	while((stack[i]!='$')&&(s[j]!='$'))
	{
		if(stack[i]==s[j])
		{
			i--; j++;
		}
		switch(stack[i])
		{	
			case 'e': str1=0;	
			break;
			case 'b': str1=1;
			break;
			case 't': str1=2;
			break;
			case 'c': str1=3;
			break;
			case 'f': str1=4;
			break;
		} 
		switch(s[j])
		{
			case 'i': str2=0;
			break;
			
			case '+' : str2=1; 
			break;
			
			case '*': str2=2;
			break;
			
			case '(': str2=3;
			break;
			
			case ')': str2=4;
			break;
			  
			case '$': str2=5;
			break;
		}
		if(m[str1][str2][0]=='\0') {
			printf("\nERROR");
			exit(0);
		} 
		else if(m[str1][str2][0]=='n') 
			i--;
		else if(m[str1][str2][0]=='i') 
			stack[i]='i';
		else
		{
			for (k=size[str1][str2]-1; k>=0;k--) {
				stack[i]=m[str1][str2][k];
			  	i++;
			}
			i--;
		} 
		for (k=0;k<=i; k++)
			printf("%c", stack[k]);
		printf("      ");
		for (k=j;k<=n; k++)
		 	printf("%c",s[k]); 
		printf(" \n");
	} 
	printf("\n SUCCESS"); 
	return 0;

}