Missing parentheses (quarters > 0), also there is no then statement in C++
Unbalanced parentheses around condition, use: if (1 + x > pow(x, sqrt(2))) y = y + x;
(x = 1) and (x = 2) are assignments, not comparisons, use (x == 1) and (x == 2) instead.
Doesn't make sense to form and of x and y. Should be if (x == 0 and y == 0)
Invalid condition, use if(1 <= x and x <= 10) instead.
There is no way for the condition to evaluate true. s cannot simultaneously be not equal to nick, penn, dime or quar. If s must be one of the choices, use the following instead:
```
if (s != "nick" and s != "penn" and s != "dime" and s != "quar") 
cout << "Input error !");
```

Can't form or of two strings. Instead, use

if (input == "N" or input == "NO") 
   . . .

Attempts to use the value for x read from a failed input stream. Use if (!cin.fail()) ...

Braces are needed to make the test for country == "China" work properly. Use the following insteadl

 language = "English"; 
 if (country == "USA") 
	{  if ( state == "PR")
       language = "Spanish"; 
	} 
 else if (country == "China") 
  	 language = "Chinese";