C Program to crate lexical analyzer which will do space removal.

#include
#include
#include
#include

int key = 0;
char expr[100];
char cont[][20]={"CONTROLS","for","do","while","NULL",};
char cond[][20]={"CONDITION","if","then","NULL"};
char oprt[][20]={"OPERATOR","+","-","*","/","%","<","<=",">",">=","=","(",")","NULL"};
char branch[][20]={"BRANCHING","goto","jump" ,"NULL"};

void checking(char[],char[][20]);

void main()
{
int i,j,l,k,m,n;
char sbexpr[50],txt[3];
clrscr();
cout<<"Enter the expression:";
gets(expr);
for(i=0;expr[i]!=NULL;i++)
{
key=0;
for(j=i,k=0;expr[j]!=32 && expr[j]!=NULL;i++,j++,k++)
sbexpr[k]=expr[j];
sbexpr[k]=NULL;

if(key==0) checking(sbexpr,cond);

if(key==0) checking(sbexpr,cont);

if(key==0) checking(sbexpr,branch);

if(key==0)
{
for(m=0;sbexpr[m]!=NULL;m++)
{
key=0;
txt[0]= sbexpr[m];
txt[1] = NULL;

if(key==0) checking(txt,oprt);
if((key==0) || ((sbexpr[m]>=97 && sbexpr[m]<=122) || (sbexpr[m]>=65 && sbexpr[m]<=90)))
{
cout<<"\n"<"<<"Identifier\n";
key = 1;
}
}
}
if(key == 0)
{
cout<<"\n"<"<<"Address\n";
key = 1;
}
}

getch();
}


void checking (char expr[],char check[][20])
{
for(int i=1;strcmp(check[i],"NULL")!=0;i++)
{
if(strcmp(expr,check[i])==0)
{
cout<"<key = 1;
}
}
}