srp.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

char ip[30], stack[30], temp[15], action[15];
int len, iptr = 0, sptr = 0, i;

void check()
{
    int flag = 0;
    while (1)
    {
        if (stack[sptr] == 'd' && stack[sptr - 1] == 'i')
        {
            stack[sptr - 1] = 'F';
            stack[sptr] = '\0';
            sptr--;
            flag = 1;
            printf("\n$%s\t\t%s$\t\tReduce F->id", stack, ip);
        }
        if (stack[sptr] == ')' && stack[sptr - 1] == 'E' && stack[sptr - 2] == '(')
        {
            stack[sptr - 2] = 'F';
            stack[sptr - 1] = '\0';
            sptr -= 2;
            flag = 1;
            printf("\n$%s\t\t%s$\t\tReduce F->(E)", stack, ip);
        }
        if (stack[sptr] == 'F' && stack[sptr - 1] == '*' && stack[sptr - 2] == 'T')
        {
            stack[sptr - 1] = '\0';
            sptr -= 2;
            flag = 1;
            printf("\n$%s\t\t%s$\t\tReduce T->T*F", stack, ip);
        }
        else if (stack[sptr] == 'F')
        {
            stack[sptr] = 'T';
            flag = 1;
            printf("\n$%s\t\t%s$\t\tReduce T->F", stack, ip);
        }
        if (stack[sptr] == 'T' && stack[sptr - 1] == '+' && stack[sptr - 2] == 'E' && ip[iptr] != '*')
        {
            stack[sptr - 1] = '\0';
            sptr -= 2;
            flag = 1;
            printf("\n$%s\t\t%s$\t\tReduce E->E+T", stack, ip);
        }
        else if ((stack[sptr] == 'T' && ip[iptr] == ')') || (stack[0] == 'T' && ip[iptr] == '\0') || (stack[sptr] == 'T' && ip[iptr] == '+'))
        {
            stack[sptr] = 'E';
            flag = 1;
            printf("\n$%s\t\t%s$\t\tReduce E->T", stack, ip);
        }
        if ((stack[sptr] == 'T' && ip[iptr] == '*') || (stack[sptr] == 'E' && ip[iptr] == '+') || (stack[sptr] == 'E' && ip[iptr] == ')') ||
            (stack[sptr] == '(' && ip[iptr] == 'i' && ip[iptr + 1] == 'd') || (stack[sptr] == '(' && ip[iptr] == '(') ||
            (stack[sptr] == '+' && ip[iptr] == 'i' && ip[iptr + 1] == 'd') || (stack[sptr] == '+' && ip[iptr] == '(') ||
            (stack[sptr] == '*' && ip[iptr] == 'i' && ip[iptr + 1] == 'd') || (stack[sptr] == '*' && ip[iptr] == '('))
        {
            flag = 2;
        }
        if (!strcmp(stack, "E") && ip[iptr] == '\0')
        {
            printf("\n$%s\t\t%s$\t\tACCEPT", stack, ip);
            exit(0);
        }
        if (flag == 0)
        {
            printf("\n$%s\t\t%s$\t\tREJECT", stack, ip);
            exit(0);
        }
        if (flag == 2)
            return;
        flag = 0;
    }
}

int main()
{
    printf("\t\t\tSHIFT RECDUCE PARSING\t\t\n\n");
    printf("Grammar\n");
    printf("E->E+T|T\nT->T*F|F\nF->( E )|id\n");
    printf("Enter the input string\n");
    scanf("%s", ip);
    printf("\n\nSTACK Implementation Table\n");
    printf("\nSTACK\t\tINPUT\t\tACTION\n");
    printf("_______\t\t_____\t\t______\n");
    printf("\n$\t\t%s$\t\t--");
    strcpy(action, "Shift ");
    if (ip[iptr] == '(')
    {
        temp[0] = ip[iptr];
        temp[1] = '\0';
    }
    else
    {
        temp[0] = ip[iptr];
        temp[1] = ip[iptr + 1];
        temp[2] = '\0';
    }
    strcat(action, temp);
    len = strlen(ip);
    for (i = 0; i < len; i++)
    {
        if (ip[iptr] == 'i' && ip[iptr + 1] == 'd')
        {
            stack[sptr] = ip[iptr];
            sptr++;
            ip[iptr] = ' ';
            iptr++;
            stack[sptr] = ip[iptr];
            stack[sptr + 1] = '\0';
            ip[iptr] = ' ';
            iptr++;
        }
        else
        {
            stack[sptr] = ip[iptr];
            stack[sptr + 1] = '\0';
            ip[iptr] = ' ';
            iptr++;
        }
        printf("\n$%s\t\t%s$\t\t%s", stack, ip, action);
        strcpy(action, "Shift ");
        if (ip[iptr] == '(' || ip[iptr] == ')' || ip[iptr] == '+' || ip[iptr] == '*')
        {
            temp[0] = ip[iptr];
            temp[1] = '\0';
        }
        else
        {
            temp[0] = ip[iptr];
            temp[1] = ip[iptr + 1];
            temp[2] = '\0';
        }
        strcat(action, temp);
        check();
        sptr++;
    }
    sptr++;
    check();
}