Why is this run time error occurring as "Unable to open Maths.lib"
#include<iostream.h>
#include<conio.h>
char username[20];
char plain_text[20];
char cipher_text[20];
char encrypt(char,int);
void main()
{
cout<<"\n Enter your username";
cin>>username;
cout<<"\n Enter your password (it must be only characters)";
cin>>plain_text;
for(int i=0;i<20;i++)
{
switch(plain_text[i])
{
case 'a':
cipher_text[i]=encrypt(plain_text[i],i);
break;
case 'b':
cipher_text[i]=encrypt(plain_text[i],i);
break;
case 'c':
cipher_text[i]=encrypt(plain_text[i],i);
break;
case 'd':
cipher_text[i]=encrypt(plain_text[i],i);
break;
case 'e':
cipher_text[i]=encrypt(plain_text[i],i);
break;
case 'f':
cipher_text[i]=encrypt(plain_text[i],i);
break;
case 'g':
cipher_text[i]=encrypt(plain_text[i],i);
break;
case 'h':
cipher_text[i]=encrypt(plain_text[i],i);
break;
case 'i':
cipher_text[i]=encrypt(plain_text[i],i);
break;
case 'j':
cipher_text[i]=encrypt(plain_text[i],i);
break;
case 'k':
cipher_text[i]=encrypt(plain_text[i],i);
break;
case 'l':
cipher_text[i]=encrypt(plain_text[i],i);
break;
case 'm':
cipher_text[i]=encrypt(plain_text[i],i);
break;
case 'n':
cipher_text[i]=encrypt(plain_text[i],i);
break;
case 'o':
cipher_text[i]=encrypt(plain_text[i],i);
break;
case 'p':
cipher_text[i]=encrypt(plain_text[i],i);
break;
case 'q':
cipher_text[i]=encrypt(plain_text[i],i);
break;
case 'r':
cipher_text[i]=encrypt(plain_text[i],i);
break;
case 's':
cipher_text[i]=encrypt(plain_text[i],i);
break;
case 't':
cipher_text[i]=encrypt(plain_text[i],i);
break;
case 'u':
cipher_text[i]=encrypt(plain_text[i],i);
break;
case 'v':
cipher_text[i]=encrypt(plain_text[i],i);
break;
case 'w':
cipher_text[i]=encrypt(plain_text[i],i);
break;
case 'x':
cipher_text[i]=encrypt(plain_text[i],i);
break;
case 'y':
cipher_text[i]=encrypt(plain_text[i],i);
break;
case 'z':
cipher_text[i]=encrypt(plain_text[i],i);
break;
default: cout<<"\n Please enter only lowercase characters";
break;
}
}
cout<<"The encrypted password is:- ";
for(i=0;i<20;i++)
{
cout<<cipher_text[i];
}
getch();
}
char encrypt(char letter,int j)
{
int i=j;
switch(letter)
{
case 'a':
letter=plain_text[i+5];
break;
case 'b':
letter=plain_text[i+5];
break;
case 'c':
letter=plain_text[i+5];
break;
case 'd':
letter=plain_text[i+5];
break;
case 'e':
letter=plain_text[i+5];
break;
case 'f':
letter=plain_text[i+5];
break;
case 'g':
letter=plain_text[i+5];
break;
case 'h':
letter=plain_text[i+5];
break;
case 'i':
letter=plain_text[i+5];
break;
case 'j':
letter=plain_text[i+5];
break;
case 'k':
letter=plain_text[i+5];
break;
case 'l':
letter=plain_text[i+5];
break;
case 'm':
letter=plain_text[i+5];
break;
case 'n':
letter=plain_text[i+5];
break;
case 'o':
letter=plain_text[i+5];
break;
case 'p':
letter=plain_text[i+5];
break;
case 'q':
letter=plain_text[i+5];
break;
case 'r':
letter=plain_text[i+5];
break;
case 's':
letter=plain_text[i+5];
break;
case 't':
letter=plain_text[i+5];
break;
case 'u':
letter=plain_text[i+5];
break;
case 'v':
letter=plain_text[i+0];
break;
case 'w':
letter=plain_text[i+1];
break;
case 'x':
letter=plain_text[i+2];
break;
case 'y':
letter=plain_text[i+3];
break;
case 'z':
letter=plain_text[i+4];
break;
default: cout<<"\n Please enter only lowercase characters";
break;
}
return letter;
}