If a grammar is left recursive, then after removing left recursion grammar becomes LL code example
Example: Write a program to check whether a grammar is left recursive or not, if it is remove left recursion
1: #include<stdio.h>
2: #include<string.h>
3: #define SIZE 10
4: int main () {
5: char non_terminal;
6: char beta,alpha;
7: int num;
8: char production[10][SIZE];
9: int index=3; /* starting of the string following "->" */
10: printf("Enter Number of Production : ");
11: scanf("%d",&num);
12: printf("Enter the grammar as E->E-A :\n");
13: for(int i=0;i<num;i++){
14: scanf("%s",production[i]);
15: }
16: for(int i=0;i<num;i++){
17: printf("\nGRAMMAR : : : %s",production[i]);
18: non_terminal=production[i][0];
19: if(non_terminal==production[i][index]) {
20: alpha=production[i][index+1];
21: printf(" is left recursive.\n");
22: while(production[i][index]!=0 && production[i][index]!='|')
23: index++;
24: if(production[i][index]!=0) {
25: beta=production[i][index+1];
26: printf("Grammar without left recursion:\n");
27: printf("%c->%c%c\'",non_terminal,beta,non_terminal);
28: printf("\n%c\'->%c%c\'|E\n",non_terminal,alpha,non_terminal);
29: }
30: else
31: printf(" can't be reduced\n");
32: }
33: else
34: printf(" is not left recursive.\n");
35: index=3;
36: }
37: }