C Program to implement Recursive Deceptive Parsing

#include
#include
#include
void main()
{
int i,j,k;
char a[20],b[20],c[20],m,n[10],o[10];
clrscr();
printf("Enter a recursive string:");
gets(a);
if(a[0]==a[3]) {
m=a[0];
printf("%c\n",m);
}
else {
printf("Entered string is not recursive");
}
j=0;
for(i=4;a[i]!=NULL;i++) {
if(a[i]!='/') {
b[j++]=a[i];
printf("%c",b[j]);
}
else {
goto a1;
}
}
a1:
b[j]='\0';
j=0;
for(i=i+1;a[i]!=NULL;i++) {
c[j]=a[i];
j++;
}
c[j]='\0';
n[0]=m;
n[1]='-';
n[2]='>';
j=3;
for(i=0;c[i]!=NULL;i++) {
n[j]=c[i];
j++;
}
n[j++]=m;
n[j++]='`';
n[j++]='\0';
printf("\n\nOutput string1 is:");
puts(n);
o[0]=m;
o[1]='-';
o[2]='>';
j=3;
for(i=0;b[i]!=NULL;i++)
{
o[j]=b[i];
j++;
}
puts(b);
o[j++]=m;
o[j++]='`';
o[j++]='/';
o[j++]='$';
o[j++]='\0';
printf("\n\nOutput string is:");
puts(o);
getch();
}

C Program to implement Recursive Descentive Parsing.

#include

#include

#include

#include

#include

char ip_sym[15],ip_ptr=0,op[50],tmp[50];

void e_prime();

void e();

void t_prime();

void t();

void f();

void advance();

int n=0;

void e(){

            strcpy(op,"TE'");

 printf("E=%-25s",op);

 printf("E->TE'\n");

            t();

 e_prime();

}

void e_prime(){

int i,n=0,l;

for(i=0;i<=strlen(op);i++)

            if(op[i]!='e')

 tmp[n++]=op[i];

strcpy(op,tmp);

l=strlen(op);

for(n=0;n < l && op[n]!='E';n++);

if(ip_sym[ip_ptr]=='+')            {

                         i=n+2;

 do {

                                    op[i+2]=op[i];

 I++;

                        }while(i<=l);

                         op[n++]='+';

                        op[n++]='T';

                        op[n++]='E';

                        op[n++]=39;

                        printf("E=%-25s",op);

                        printf("E'->+TE'\n");

                        advance();

                        t();

e_prime();

            }

else{

                        op[n]='e';

                        for(i=n+1;i<=strlen(op);i++)

                        op[i]=op[i+1];

                        printf("E=%-25s",op);

                        printf("E'->e");

}

}

void t(){

 int i,n=0,l;

            for(i=0;i<=strlen(op);i++)

            if(op[i]!='e')

            tmp[n++]=op[i];

            strcpy(op,tmp);

            l=strlen(op);

for(n=0;n < l && op[n]!='T';n++);

i=n+1;

            do{

                        op[i+2]=op[i];

                        i++;

            }while(i < l);

            op[n++]='F';

            op[n++]='T';

 op[n++]=39;

            printf("E=%-25s",op);

            printf("T->FT'\n");

 f();

 t_prime();

}

void t_prime(){

int i,n=0,l;

for(i=0;i<=strlen(op);i++)

             if(op[i]!='e')

            tmp[n++]=op[i];

strcpy(op,tmp);

l=strlen(op);

for(n=0;n < l && op[n]!='T';n++);

if(ip_sym[ip_ptr]=='*')            {

                         i=n+2;

 do{

                                    op[i+2]=op[i];

                                    i++;

                        }while(i < l);

                        op[n++]='*';

                        op[n++]='F';

                        op[n++]='T';

                        op[n++]=39;

                        printf("E=%-25s",op);

                        printf("T'->*FT'\n");

                        advance();

                        f();

                        t_prime();

            }

            else{

op[n]='e';

            for(i=n+1;i<=strlen(op);i++)

            op[i]=op[i+1];

            printf("E=%-25s",op);

            printf("T'->e\n");

            }

}

void f(){

int i,n=0,l;

for(i=0;i<=strlen(op);i++)

             if(op[i]!='e')

 tmp[n++]=op[i];

            strcpy(op,tmp);

l=strlen(op);

for(n=0;n < l && op[n]!='F';n++);

            If((ip_sym[ip_ptr]=='i')||(ip_sym[ip_ptr]=='I')){

                        op[n]='i';

                        printf("E=%-25s",op);

                        printf("F->i\n");

                        advance();

            }

            else{

                        if(ip_sym[ip_ptr]=='(')                         {

                                    advance();

                                    e();

                                    if(ip_sym[ip_ptr]==')'){

                                                advance();

                                                i=n+2;

                                                do{

                                                            op[i+2]=op[i];

                                                            i++;

                                                }while(i<=l);

                                    op[n++]='(';

                                    op[n++]='E';

                                    op[n++]=')';

                                    printf("E=%-25s",op);

                                    printf("F->(E)\n");

                        }

            }

            else{

                        printf("\n\t syntax error");

                        getch();

                        exit(1);

                        }

            }

}

void advance(){

            ip_ptr++;

}

void main(){

            int i;

            clrscr();

            printf("\nGrammar without left recursion");

 printf("\n\t\t E->E+T/T \n\t\t T->T*F/F \n\t\t F->(E)/Id ");

 printf("\n Enter the input expression:");

            gets(ip_sym);

            printf("Expressions");

            printf("\t Sequence of production rules\n");

            e();

            for(i=0;i < strlen(ip_sym);i++){

                        if(ip_sym[i]!='+'&&ip_sym[i]!='*'&&ip_sym[i]!='('&&

                        ip_sym[i]!=')'&&ip_sym[i]!='i'&&ip_sym[i]!='I'){

                                    printf("\nSyntax error");

                                    break;

                        }

                        for(i=0;i<=strlen(op);i++)

                        if(op[i]!='e')

                        tmp[n++]=op[i];

                        strcpy(op,tmp);

                        printf("\nE=%-25s",op);

            }

            getch();

}

C Program To Find Follow Of Given String.

#include

#include

intn,m=0,p,i=0,j=0;

char a[10][10],f[10];

void follow(char c);

void first(char c);

int main()

{

inti,z;

charc,ch;

printf("Enter the no.of productions:");

scanf("%d",&n);

printf("Enter the productions(epsilon=$):\n");

for(i=0;i

scanf("%s%c",a[i],&ch);

do{

m=0;

printf("Enter the element whose FOLLOW is to be found:");

scanf(" %c",&c);

follow(c);

printf("FOLLOW(%c) = { ",c);

for(i=0;i

printf("%c ",f[i]);

printf(" }\n");

printf("Do you want to continue(0/1)?");

scanf("%d%c",&z,&ch);

}         

while(z==1);

}

void follow(char c)

{

            if(a[0][0]==c)f[m++]='$';

for(i=0;i

{

for(j=2;j

{

if(a[i][j]==c)

{

if(a[i][j+1]!='\0')first(a[i][j+1]);

if(a[i][j+1]=='\0'&&c!=a[i][0])

follow(a[i][0]);

                                                }

}

}

}

void first(char c){

int k;

if(!(isupper(c)))f[m++]=c;

for(k=0;k

{

if(a[k][0]==c)

{

if(a[k][2]=='$') follow(a[i][0]);

else

if(islower(a[k][2]))f[m++]=a[k][2];

else first(a[k][2]);

}

}

}

C Program To Find First Of Given Sting

#include

#include

void FIRST(char );

intcount,n=0;

charprodn[10][10], first[10];

main(){

inti,choice;

charc,ch;

printf("How many productions ? :");

scanf("%d",&count);

printf("Enter Number Of Productions  :");

for(i=0;i

scanf("%s%c",prodn[i],&ch);

do{

n=0;

printf("Element :");

scanf("%c",&c);

FIRST(c);

printf("\n FIRST(%c)= { ",c);

for(i=0;i

printf("%c ",first[i]);

printf("}\n");

printf("press 1 to continue : ");

scanf("%d%c",&choice,&ch);

}

while(choice==1);

}

void FIRST(char c){

int j;

if(!(isupper(c)))first[n++]=c;

for(j=0;j

if(prodn[j][0]==c){

if(prodn[j][2]=='$') first[n++]='$';

else

if(islower(prodn[j][2]))first[n++]=prodn[j][2];

else FIRST(prodn[j][2]);

}

}

}

C Program to Draw Pascal's triangle

           1
         1   1
       1   2   1
     1   3   3    1
   1  4    6   4   1
 1  5   10   10  5   1


#include
int main()
{
    int rows,coef=1,space,i,j;
    printf("Enter number of rows: ");
    scanf("%d",&rows);
    for(i=0;i    {
        for(space=1;space<=rows-i;space++)
        printf("  ");
        for(j=0;j<=i;j++)
        {
            if (j==0||i==0)
                coef=1;
            else
               coef=coef*(i-j+1)/j;
            printf("%4d",coef);
        }
        printf("\n");
    }
}

Write a C program to display reverse pyramid.

* * * * * * * * *
  * * * * * * *
    * * * * *
      * * *
        *


 #include
void  main()
{
    int rows,i,j,space;
    printf("Enter number of rows: ");
    scanf("%d",&rows);
    for(i=rows;i>=1;--i)
    {
        for(space=0;space           printf("  ");
        for(j=i;j<=2*i-1;++j)
          printf("* ");
        for(j=0;j            printf("* ");
        printf("\n");
    }
    return 0;
}

C Program to print half pyramid as using number

#include
int main()
{
    int i,j,rows;
    printf("Enter the number of rows: ");
    scanf("%d",&rows);
    for(i=1;i<=rows;++i)
    {
        for(j=1;j<=i;++j)
        {
           printf("%d ",j);
        }
        printf("\n");
    }
    return 0;
}

1
1 2
1 2 3
1 2 3 4
1 2 3 4 5