P R I N C I P L E S OF C O M P I L E R D E S I G N ( P C D )
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1. |
Program on Lexical Analyzer |
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#include<stdio.h> #include<conio.h> #include<ctype.h> #include<stdlib.h> #include<string.h> #include<fstream.h> int cb; char *ch; void disdash() { for(int i=1;i<=80;i++) cout<<'-'; } void getpro() { cb=1; ofstream outfile("Temp.txt"); clrscr(); printf("Write program with last line single char as '~' :\n"); while(cb) { printf(": "); while ((*ch = getchar()) != '\n') { if (*ch=='~') cb=0; else outfile.put(*ch); } if (cb==1) outfile.put('\n'); } outfile.close(); } void putpro() { ifstream infile("Temp.txt"); printf("\nYour Program is :\n"); printf(": "); while( infile ) { infile.get(*ch); printf("%c",*ch); if(*ch=='\n') printf(": "); } printf("\n"); infile.close(); } void analysis() { int tbc,i,j,got; char str[80],*b=""; char kw[5][6] = {"BEGIN","END","IF","THEN","ELSE"}; char op[7][3] = {"<","<=","==","<>",">",">=","="}; char al[26][2] = {"A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"}; char dg[10][2] = {"0","1","2","3","4","5","6","7","8","9"}; disdash(); printf("Sr.No\t\tToken\t\t\tCode\t\t\tValue\n"); disdash(); ifstream infile("Temp.txt"); tbc=1; strcpy(str,b); while(infile) { infile.get(*ch); if( (*ch==' ')||(*ch=='\n') ) { if (stricmp(str,b)) { /* Keword Check */ got=0; for(i=0;i<5;i++) { j = stricmp(str,kw[i]); if(j==0) { printf("%d",tbc); printf("\t\t%s",str); printf("\t\t\t%d",i+1); printf("\t\t\t -\n"); strcpy(str,b); tbc++; got=1; break; } } /* Operator Check */ if (got==0) { for(i=0;i<7;i++) { j = stricmp(str,op[i]); if(j==0) { printf("%d",tbc); printf("\t\t%s",str); printf("\t\t\t8"); printf("\t\t\t %d\n",i+1); strcpy(str,b); tbc++; got=1; break; } } } /*Identifier Check*/ if (got==0) { for(i=0;i<26;i++) { if( (str[0]==*al[0,i]) || (toupper(str[0])==*al[0,i]) ) { printf("%d",tbc); printf("\t\t%s",str); printf("\t\t\t6"); printf("\t\t\t%d\n",&str); strcpy(str,b); tbc++; got=1; break; } else if(str[0] == *dg[0,i]) { printf("%d",tbc); printf("\t\t%s",str); printf("\t\t\t7"); printf("\t\t\t%d\n",&str); strcpy(str,b); tbc++; got=1; break; } } } /*Error Msg*/ if(got==0) { printf("ERROR :: Invalid sysmbol found."); printf("%s",str); printf("Plese enter proper code..."); getch(); infile.close(); fflush(stdin); exit(0); } } } else strcat(str,ch); } infile.close(); fflush(stdin); } void main() { clrscr(); getpro(); putpro(); analysis(); getch(); } |
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2. |
program for top down parsing [ S->cAd A->ad/d input productions ] |
| #include<iostream.h> #include<stdlib.h> #include<stdio.h> #include<conio.h> #include<string.h> char string[30]; int length,ptr=0,temp,flag; void Advance() //increment the ptr by 1 { ptr++; } int A(void) //function for Production A { temp=ptr; if (string[ptr]=='a') { Advance(); if (string[ptr]=='d') { Advance(); return 1; } } ptr=temp; //failure to find ab in given string if (string[ptr]=='d') { Advance(); return 1; } else return 0; } int S() //function for production S { int val; if (string[ptr]=='c') { Advance(); val=A(); if (val) if (string[ptr]=='d') { Advance(); printf("\nThe given string is accepted by the grammer."); flag=1; getch(); return 1; } } return 0; } void main() { clrscr(); puts("Enter the String:"); gets(string); //get the input string length=strlen(string); printf("\n %d",length); S(); if (flag!=1) printf("\nThe given string is NOT accepted by the grammer. "); getch(); } |
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3. |
program for generation of symbol table. |
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#include<iostream.h> #include<conio.h> #include<stdio.h> #include<string.h> #include<process.h> struct node { char nav[10],info[10]; struct node *next; }*first; void add(); void search(); void showtab(); int del(); void add() { struct node *navin; navin = new node; cout<<"Enter the name\n"; gets(navin->nav); cout<<"Enter the info\n"; gets(navin->info); navin->next=first; first=navin; } void search() { char tnav[10]; cout<<"Enter the name to be searched\n"; gets(tnav); struct node *tmp; tmp=first; int tru=1; while(tmp!=NULL) { tru=strcmp(tmp->nav,tnav); if(!tru) break; tmp=tmp->next; } if(tmp==NULL) cout<<"No match found"; else cout<<tmp->nav<<"\t"<<tmp->info<<"\n"; getch(); } int del() { char tnav[10]; cout<<"Enter the name to be deleted\n"; gets(tnav); int tru=1; tru=strcmp(first->nav,tnav); if(!tru) { first=first->next; return 0; } struct node *t,*p; t=first; p=first->next; while(p!=NULL) { tru=strcmp(p->nav,tnav); if(!tru) { t->next=p->next; break; } else { t=t->next; p=p->next; } } getch(); return 0; } void showtab() { struct node *tmp; tmp=first; cout<<"Name \t"<<"Info \n"; while(tmp!=NULL) { cout<<tmp->nav<<"\t"<<tmp->info<<"\n"; tmp=tmp->next; } getch(); } void main() { clrscr(); first=NULL; int ch; while(1) { clrscr(); cout<<"Type \n1. To add\n2. To del\n3. To search\n4. To show table\n5. To exit\n"; cin>>ch; switch(ch) { case 1: add(); break; case 2: del(); break; case 3: search(); break; case 4: showtab(); break; case 5: exit(0); break; default: break; } } getch(); } |
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