Ppl Prolog

Write a predicate in Prolog to center string in a filed of 80 characters. Solution: domains NN,N,Y = integer predicates go write_right_space(integer) write_spaces(integer) clauses: go:N = 10, write_right_spaces(N). write_right_spaces(N):Y = 80 – N; Write_spaces(Y). write_spaces(0):- !. write_spaces(x):write(“ “), NN=x-1; Write_spaces(NN).

Write a Prolog predicates strops(imputstring, substring, startpos) that returns the starting position of substring in the given input string as startpos Solution domains: SS=string predicates: go strops(string, string, integer) search(string, string, integer, integer) clauses go:- write(“Enter I/P string : ”); readln( I ) write(“Enter search string :”); readln( S ) str_len( I , 11 ), str_len( S , 12 ), L2 <= L1 strops( I , S , - ). go:- writte 1”Invalid Input “), n1. stropos(I,S,-) :- -str_len( S , S1 ), search(I , S , 1 , s1 ). search(I , S , 1 , s1 ) :- frontstr( S1 , I , SS , - ), SS = S, write(“ Reg string found at position ” , L ), n1, !. search(I , S , L , s1 ) :L1 = L + 1 Frontchar( I , - , I1 ), search(I , S , L1 , s1 ). search( “ “ , - , - ,- ) :write(“string not found ” ) , nl, !.

Write a Prolog program to sum ‘n’ integers and find their average. Solution domains predicates go sum( integer , integer , integer ) avg( integer ) clauses. go:- write(“Enter the number of values : ”); readln( N ), avg( N ). avg( N ) :N1 =N, S = 0; sum( N1 , S , N ) sum( o , S , N ) :A = S / N write(“In sum : ”, S ); write(“In Avg : ”, A ), nl, sum( N1 , S , N ) :- write(“Enter the value : ”); read int( x ), SS = S + x, NN = N1 – 1, sum( NN , SS , N ).

Write a Prolog program to reverse list of integer and store it in a separate list. Print the original as well as reverse list. Solution domains : list = integer* predicates : reverse_list( list , list) write_list( list ) reverse( list , list , list ) clauses : reverse_list( L1 , L2 ) :reverse( L1 , [] , L2 ), write_list( L2 ),

reverse( [] , Head | Tail] , L1 , L2):reverse( Tail , [Head | L1] , L2). write_list( [] ). write_list( [x | Tail]) :write( x ), write_list( Tail ). Write a prolog program to extract nth element given list. Solution domains 1st = symbol* predicates go extract( lst , integer , symbol ) clauses go:write(“Enter N:- ”), readint( N ), extract([a , b , c , d], N , 2) write(“Element =”, 2), nl extract([x | _ ], 1 , z):extract([ _ | Tail], N , z):NN = N – 1, Extract(Tail, NN , z). Write a prolog program which counts number of words in a given input string solution domains str = string predicates: go no_words(string , integer , integer ) clauses go:write(“Enter a string :- ”), readln( str ), no_words(str , O , N), write(“No of words = ”, N), nl. no_words(str , X , N):fronttoken(str , F , R), NOT(F = “ ”),

X1 = x + 1, no_words(R , X1 , N). no_words(_ , X , N):N = X. Write a prolog program to enter employee details using compound object emp (eno,ename,designation,salary) Solution domains e =

emp(eno , ename , desgn , salary) ename , desgn = string eno , sal = integers. predicates: read_emp(e) go clauses: go:- read_emp(emp), nl write(“Accept (y/n)? ”). Readchr(Reply), Reply = ‘ y ’, ! go:- nl , write(“please reenter”), Nl, go. Read_emp(emp(Eno , Ename , Desgn , Salary)) Write(“Enter Eno: ”), Readln( Eno ), Write(“Enter Ename: ”), Readln(Ename), Write(“Enter desgn: ”), Readln(Desgn), Write(“Enter salary ”), Readln(salary). Write a prolog program to display Fibonacci series and display sum of series Solution Sum, avg , cnt , num , cnt1 = Integer Predicates: fibo(integer , integer , integer) go clauses: go:- write(“How many terms: ”), readln( num ), sum = 0,

avg = 0, cnt = 1, fibo(num , 0 , 1), write(“sum =, ”sum) avg = sum / num, write(“Avg = ”, avg); go. Fibo(cnt , N1 , N2):Write( N1 ), Sum = sum + N1, N3 = N2, N4 = N1 + N2, cnt = cnt – 1, fibo(cnt , N3 , N4). Write a prolog program for the following 1. Check whether the given number is a prime number. 2. Check whether the given number is a perfect number. Solution 1. Prime Number Predicates go chkprime(integer , integer) clauses go:- write(“Enter the number : ”) readint( N ), x = 2, chkprime(N , X), go:- write(“Given no. is not prime”), nl chkprime(N , X):N, write(“Given no. is prime”), !. chkprime(N , X):Y = N mod X, Y = 0, !,fail. chkprime(N , X):- Y = N mod X, not(y = 0), XX = X + 1, chkprime(N , XX). 2.Perfect N domains Sum, no, cnt = integer

Predicates go perfect(integer , integer , integer) goal go clauses go:- write(“Enter No: ”), readint(No), sum1, cnt=1, perfect(No , cnt , sum) perfect(No , cnt , sum):No = cnt, No = sum, Write(“Number is perfect”), !. perfect(No , cnt , sum):No = cnt, sum < > No Write(“Number is not perfect”), !. perfect(No , cnt , sum):No < > cnt N1 = No mod cnt, N1 = 0 Sum1 = sum1 + cnt, Cnt1 = cnt + 1, perfect(no , cnt1 , sum1). perfect(No , cnt , sum):No < > cnt N1 = No mod cnt, No < > 0 cnt2 = cnt + 1, perfect(No , cnt2 , sum).