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practical 1 (A1)

Aim​

Aim: Design a lexical analyzer for given language and the Lexical analyzer should ignore redundant spaces, tabs and new lines.

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code​

    #include<stdio.h> //header file
    #include<string.h> //header file
    int main() //main function
    {
        int c=1,i,j=0; //declaring variables
        char file_name[20],s[20];
        scanf("%s",file_name);
        FILE *fp;
        fp=fopen(file_name,"r");
        if(fp == NULL) //if condition
        {
            printf("Failed to open the file");
        }
        else //else condition
        {
            do{
                fscanf(fp,"%s",s);
                if(s[0]=='#' && s[7]=='e')
                {
                    printf("%s is a Header file\n",s);
                }
                else if(!strcmp(s,"+") || !strcmp(s,"-") || !strcmp(s,"*") 
                    || !strcmp(s,"/") || !strcmp(s,">") || !strcmp(s,"<") || 
                    !strcmp(s,"=") || !strcmp(s,"<=") || 
                    !strcmp(s,">=") || !strcmp(s,"!") || !strcmp(s,"!=") || 
                    !strcmp(s,"==") || 
                    !strcmp(s,"++") || !strcmp(s,"--") || 
                    !strcmp(s,"&") || !strcmp(s,"|") || !strcmp(s,"||") || !strcmp(s,"&&") 
                    || 
                    !strcmp(s,"%"))
                    {
                        printf("%s is an Operator\n",s);
                    }
                else if(!strcmp(s,"auto") ||!strcmp(s,"break") 
                ||!strcmp(s,"case") || !strcmp(s,"char") || !strcmp(s,"const") || 
                !strcmp(s,"continue") || !strcmp(s,"default") || 
                !strcmp(s,"do") || !strcmp(s,"double") || !strcmp(s,"else") || 
                !strcmp(s,"enum") || !strcmp(s,"extern") || 
                !strcmp(s,"float") || !strcmp(s,"for") || !strcmp(s,"goto") || 
                !strcmp(s,"if") || !strcmp(s,"int") || 
                !strcmp(s,"long") || !strcmp(s,"register") || !strcmp(s,"return") || 
                !strcmp(s,"short") || !strcmp(s,"signed") || 
                !strcmp(s,"sizeof") || !strcmp(s,"static") || !strcmp(s,"struct") || 
                !strcmp(s,"switch") || !strcmp(s,"typedef") || 
                !strcmp(s,"union") || !strcmp(s,"unsigned") || !strcmp(s,"void") || 
                !strcmp(s,"volatile") || !strcmp(s,"while"))
                {
                     printf("%s is a Keyword\n",s);
                }
                else if(!strcmp(s,"\""))
                {
                    fscanf(fp,"%s",s);
                    while(strcmp(s,"\""))
                    {
                        printf("%s ",s);
                        fscanf(fp,"%s",s);
                    }
                    printf("is an Argument\n");
                }
                else if(!strcmp(s,"scanf") || !strcmp(s,"printf") || 
                !strcmp(s,"main"))
                {
                     printf("%s is an Identifier\n",s);
                }
                else if(!strcmp(s,",") || !strcmp(s,";") || !strcmp(s,"{") 
                || !strcmp(s,"}") || !strcmp(s,"(") || !strcmp(s,")"))
                {
                    continue;
                }
                else
                {
                    printf("%s is an Identifier\n",s);
                }
            }while(c != EOF);
        }
        fclose(fp);
        return 0;
    }

Input file​

make another file abcd.c.

abcd.c

    #include<stdio.h>
    #include<stdlib.h>
    int main ( )
    {
        int a , b , c , ch ;
        printf ( " \n ENTER numbers as an argument " ) ;
        scanf ( " %d%d " , & a , & b ) ;
        printf ( " \nMENU\n1.ADD\n2.Sub\n3.MUL " ) ;
        scanf ( " %d " , & ch ) ;
        c = a + b ;
        if ( ch == 0 )
        {
            printf ( " bye " ) ;
        }
    }

Commands​

gcc a1.c
.\a.exe
abcd.c

Output​

image