Operator Precedence Parse Program in C

Operator Precedence Parse Program in C-

Program-

#include<stdio.h>

#include<conio.h>

void main() {

  char stack[20], ip[20], opt[10][10][1], ter[10];

  int i, j, k, n, top = 0, col, row;

  clrscr();

  for (i = 0; i < 10; i++) {

    stack[i] = NULL;

    ip[i] = NULL;

    for (j = 0; j < 10; j++) {

      opt[i][j][1] = NULL;

    }

  }

  printf("Enter the no.of terminals :\n");

  scanf("%d", & n);

  printf("\nEnter the terminals :\n");

  scanf("%s", & ter);

  printf("\nEnter the table values :\n");

  for (i = 0; i < n; i++) {

    for (j = 0; j < n; j++) {

      printf("Enter the value for %c %c:", ter[i], ter[j]);

      scanf("%s", opt[i][j]);

    }

  }

  printf("\n**** OPERATOR PRECEDENCE TABLE ****\n");

  for (i = 0; i < n; i++) {

    printf("\t%c", ter[i]);

  }

  printf("\n");

  for (i = 0; i < n; i++) {

    printf("\n%c", ter[i]);

    for (j = 0; j < n; j++) {

      printf("\t%c", opt[i][j][0]);

    }

  }

  stack[top] = '$';

  printf("\nEnter the input string:");

  scanf("%s", ip);

  i = 0;

  printf("\nSTACK\t\t\tINPUT STRING\t\t\tACTION\n");

  printf("\n%s\t\t\t%s\t\t\t", stack, ip);

  while (i <= strlen(ip)) {

    for (k = 0; k < n; k++) {

      if (stack[top] == ter[k])

        col = k;

      if (ip[i] == ter[k])

        row = k;

    }

    if ((stack[top] == '$') && (ip[i] == '$')) {

      printf("String is accepted\n");

      break;

    } else if ((opt[col][row][0] == '<') || (opt[col][row][0] == '=')) {

      stack[++top] = opt[col][row][0];

      stack[++top] = ip[i];

      printf("Shift %c", ip[i]);

      i++;

    } else {

      if (opt[col][row][0] == '>') {

        while (stack[top] != '<') {

          --top;

        }

        top = top - 1;

        printf("Reduce");

      } else {

        printf("\nString is not accepted");

        break;

      }

    }

    printf("\n");

    for (k = 0; k <= top; k++) {

      printf("%c", stack[k]);

    }

    printf("\t\t\t");

    for (k = i; k < strlen(ip); k++) {

      printf("%c", ip[k]);

    }

    printf("\t\t\t");

  }

  getch();

}

/*

OutPut of Operator Precedence Parse Program in C-

Enter the value for * *:>
Enter the value for * $:>                                                       
Enter the value for $ i:<                                                       
Enter the value for $ +:<                                                       
Enter the value for $ *:<                                                       
Enter the value for $ $:accept                                                  
                                                                                
**** OPERATOR PRECEDENCE TABLE ****                                             
        i       +       *       $                                               
                                                                                
i       e       >       >       >                                               
+       <       >       <       >                                               
*       <       >       >       >                                               
$       <       <       <       a
*/
Enter the input string:                                                         
i*i                                                                             
                                                                                
STACK                   INPUT STRING                    ACTION                  
                                                                                
$                       i*i                     Shift i                         
$<i                     *i                      Reduce                          
$                       *i                      Shift *                         
$<*                     i                       Shift i                         
$<*<i                                                                           
String is not accepted