C program to implement lexical analyzer

// Aim: Lexical Analyzer

#include<conio.h>

#include<string.h>

#include<ctype.h>

#include<stdio.h>

class Lex_Ana
{
public :
int i,j,k,ti,oprfl,delfl,keyfl,Litfl,cLitfl,ptfl,tfl,mxIdeni,Liti,mxIdenj,mxOpri,mxOprj,mxDeli,Erri;
int uqIdi,uqOpi,uqDei,defOpi,defKeyi,cLiti;
char mStr[50],mxIden[20][20],mxOpr[20][20],mxDel[20],tmpStr[50];
char defOprStr[20][20],defOpr[15],defDel[15],defKey[20][20];
char uqOpr[20][20],uqIden[20][20],uqIdfl[20],uqOpfl[20],uqDefl[20],uqDel[20];
char Opr[20][20],invalTok[20][20],Con[20][20],Iden[20][20],
Key[20][20],inTok[20],Lit[20][20],Err[20][20],cLit[20][20];
int Opri,invToki,Coni,Ideni,Keyi,Deli,inToki;

Lex_Ana(char *str)
{
strcpy(mStr,str);

//Defined Keywords
defKeyi=13;
strcpy(defKey[0],”int”);
strcpy(defKey[1],”float”);
strcpy(defKey[2],”double”);
strcpy(defKey[3],”for”);
strcpy(defKey[4],”if”);
strcpy(defKey[5],”else”);
strcpy(defKey[6],”while”);
strcpy(defKey[7],”do”);
strcpy(defKey[8],”return”);
strcpy(defKey[9],”char”);
strcpy(defKey[10],”break”);
strcpy(defKey[11],”goto”);
strcpy(defKey[12],”void”);

//Defined Operators
defOpi=18;
strcpy(defOprStr[0],”+”);
strcpy(defOprStr[1],”-“);
strcpy(defOprStr[2],”*”);
strcpy(defOprStr[3],”/”);
strcpy(defOprStr[4],”%”);
strcpy(defOprStr[5],”=”);
strcpy(defOprStr[6],”<“);
strcpy(defOprStr[7],”>”);
strcpy(defOprStr[8],”<=”);
strcpy(defOprStr[9],”>=”);
strcpy(defOprStr[10],”==”);
strcpy(defOprStr[11],”=+”);
strcpy(defOprStr[12],”=-“);
strcpy(defOprStr[13],”=*”);
strcpy(defOprStr[14],”=/”);
strcpy(defOprStr[15],”=%”);
strcpy(defOprStr[16],”++”);
strcpy(defOprStr[17],”–“);
strcpy(defOpr,”+-/*%=<>”);
strcpy(defDel,”;,:{}[]()”);
}

int IsMxIden(char ch)
{
return((IsIden(ch)||IsFloat(ch))?1:0);
}

int IsIden(char ch)
{
return((isalpha(ch)||ch==’_’)?1:0);
}

int IsFloat(char ch)
{
return((isdigit(ch)||ch==’.’)?1:0);
}

int IsOpr(char ch)
{
oprfl=0;
for(ti=0;ti<strlen(defOpr)&&!oprfl;ti++)
{
if(ch==defOpr[ti])
{
oprfl=1;
}
}
return oprfl;
}

int IsDel(char ch)
{
delfl=0;
for(ti=0;ti<strlen(defDel)&&!delfl;ti++)
{
if(ch==defDel[ti])
{
delfl=1;
}
}
return delfl;
}

int IsKey(char *str)
{
keyfl=0;
for(ti=0;ti<defKeyi&&!keyfl;ti++)
{
if(!strcmp(defKey[ti],str))
{
keyfl=1;
}
}
return keyfl;
}
void Find_Lex()
{
i=0;
cLiti=0;
Liti=0;
Erri=0;
mxIdeni=0;
mxIdenj=0;
mxOpri=0;
mxOprj=0;
mxDeli=0;
inToki=0;
while(mStr[i]!=’\0′)
{
if(IsMxIden(mStr[i]))
{
while(IsMxIden(mStr[i]))
{
mxIden[mxIdeni][mxIdenj++]=mStr[i++];
if(!IsMxIden(mStr[i]))
{
mxIden[mxIdeni++][mxIdenj]=’\0′;
mxIdenj=0;
}
}
}
else if(mStr[i]=='”‘)
{
Litfl=1;
k=0;
tmpStr[k++]=mStr[i];
for(j=i+1;j<strlen(mStr)&&Litfl;j++)
{
tmpStr[k++]=mStr[j];
if(mStr[j]=='”‘)
{
tmpStr[k]=’\0′;
strcpy(Lit[Liti++],tmpStr);
Litfl=0;
i=j+1;
}
}
if(Litfl)
{
strcpy(Err[Erri++],”Invalid Use of \””);
i++;
}
}
else if(mStr[i]==’\”)
{
cLitfl=0;
k=0;
tmpStr[k++]=mStr[i];
for(j=i+1;j<strlen(mStr)&&!cLitfl;j++)
{
tmpStr[k++]=mStr[j];
if(mStr[j]==’\”)
{
tmpStr[k]=’\0′;
if(strlen(tmpStr)!=3)
{
strcpy(Err[Erri++],”Invalid Use of \'”);
cLitfl=1;
i++;
}
else
{
strcpy(cLit[cLiti++],tmpStr);
cLitfl=1;
i=j+1;
}
}
}
if(!cLitfl)
{
strcpy(Err[Erri++],”Invalid Use of \'”);
cLitfl=1;
i++;
}
}
else if(IsOpr(mStr[i]))
{
while(IsOpr(mStr[i]))
{
mxOpr[mxOpri][mxOprj++]=mStr[i++];
if(!IsOpr(mStr[i]))
{
mxOpr[mxOpri++][mxOprj]=’\0′;
mxOprj=0;
}
}
}
else if(IsDel(mStr[i]))
{
while(IsDel(mStr[i]))
{
mxDel[mxDeli++]=mStr[i++];
}
mxDel[mxDeli]=’\0′;
}
else if(mStr[i]!=’ ‘)
{
inTok[inToki++]=mStr[i++];
inTok[inToki]=’\0′;
}
else
{
i++;
}
}
}

void Rem_Dup()
{
uqIdi=0;
uqDei=0;
uqOpi=0;
for(i=0;i<20;i++)
{
uqOpfl[i]=0;
uqIdfl[i]=0;
uqDefl[i]=0;
}
for(i=1;i<mxIdeni+1;i++)
{
if(uqIdfl[i-1]==0)
{
strcpy(uqIden[uqIdi++],mxIden[i-1]);
for(j=i;j<mxIdeni;j++)
{
if(!strcmp(mxIden[j],mxIden[i-1]))
{
uqIdfl[j]=1;
}
}
}
}
for(i=1;i<mxOpri+1;i++)
{
if(uqOpfl[i-1]==0)
{
strcpy(uqOpr[uqOpi++],mxOpr[i-1]);
for(j=i;j<mxOpri;j++)
{
if(!strcmp(mxOpr[j],mxOpr[i-1]))
{
uqOpfl[j]=1;
}
}
}
}
for(i=1;i<mxDeli+1;i++)
{
if(uqDefl[i-1]==0)
{
uqDel[uqDei++]=mxDel[i-1];
uqDel[uqDei]=’\0′;
for(j=i;j<mxDeli;j++)
{
if(mxDel[j]==mxDel[i-1])
{
uqDefl[j]=1;
}
}
}
}
}

void Sep_Val()
{
Opri=0;
invToki=0;
Ideni=0;
Coni=0;
Keyi=0;
for(i=0;i<uqIdi;i++)
{
if(IsIden(uqIden[i][0]))
{
if(IsKey(uqIden[i]))
{
strcpy(Key[Keyi++],uqIden[i]);
}
else
{
ptfl=1;
for(j=0;j<strlen(uqIden[i])&&ptfl;j++)
{
if(uqIden[i][j]==’.’)
{
strcpy(invalTok[invToki++],uqIden[i]);
ptfl=0;
}
}
if(ptfl)
{
strcpy(Iden[Ideni++],uqIden[i]);
}
}
}
else
{
tfl=1;
ptfl=0;
for(j=0;j<strlen(uqIden[i])&&tfl;j++)
{
if(IsIden(uqIden[i][j]))
{
strcpy(invalTok[invToki++],uqIden[i]);
tfl=0;
}
else if(uqIden[i][j]==’.’)
{
if(ptfl)
{
strcpy(invalTok[invToki++],uqIden[i]);
tfl=0;
}
if(!ptfl)
{
ptfl=1;
}
}
}
if(tfl)
{
strcpy(Con[Coni++],uqIden[i]);
}
}
}
for(i=0;i<uqOpi;i++)
{
tfl=1;
for(j=0;j<defOpi&&tfl;j++)
{
if(!strcmp(uqOpr[i],defOprStr[j]))
{
strcpy(Opr[Opri++],uqOpr[i]);
tfl=0;
}
}
if(tfl)
{
strcpy(invalTok[invToki++],uqOpr[i]);
}
}
}

void Display()
{
printf(“\n\n\t: Lexical Analysis Report :\n\n\n\t%c Input String: %s\n\n\n”,272,mStr);
printf(“\t%c Total Identifiers: %d\n\n”,272,Ideni);
for(i=0;i<Ideni;i++)
{
printf(“\t\t”);
puts(Iden[i]);
}
printf(“\n\t%c Total Constants: %d\n\n”,272,Coni);
for(i=0;i<Coni;i++)
{
printf(“\t\t”);
puts(Con[i]);
}
printf(“\n\t%c Total Literals: %d\n\n”,272,Liti+cLiti);
for(i=0;i<Liti;i++)
{
printf(“\t\t”);
puts(Lit[i]);
}
for(i=0;i<cLiti;i++)
{
printf(“\t\t”);
puts(cLit[i]);
}
printf(“\n\t%c Total Keywords: %d\n\n”,272,Keyi);
for(i=0;i<Keyi;i++)
{
printf(“\t\t”);
puts(Key[i]);
}
printf(“\n\t%c Total Operators: %d\n\n”,272,Opri);
for(i=0;i<Opri;i++)
{
printf(“\t\t”);
puts(Opr[i]);
}
printf(“\n\t%c Total Delimeters: %d\n\n”,272,uqDei);
if(uqDei)
{
printf(“\t\t”);
puts(uqDel);
}
printf(“\n\t%c Total Invalid Tokens: %d\n\n”,272,invToki+inToki);
for(i=0;i<invToki;i++)
{
printf(“\t\t”);
puts(invalTok[i]);
}
if(inToki)
{
for(i=0;i<strlen(inTok);i++)
{
printf(“\t\t”);
printf(“%c\n”,inTok[i]);
}
}
printf(“\n\t%c Invalid Used Tokens: %d\n\n”,272,Erri);
for(i=0;i<Erri;i++)
{
printf(“\t\t”);
puts(Err[i]);
}
}

};

void main()
{
clrscr();
char mstr[50];
printf(“\n\n\tEnter String: “);
gets(mstr);
Lex_Ana oblex(mstr);
oblex.Find_Lex();
oblex.Rem_Dup();
oblex.Sep_Val();
oblex.Display();
getch();
}

Output:

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