Common Errors and Steps to Rectify these errors while compiling C and C++ Programs

S.No.	Common Errors	Rectification
1.	Statement missing ;	‘;’ should be placed at the end of the statement.
2.	Undefined symbol/variable.	Declaration of the data type should be done for the variable.
3.	Function ‘clrscr’ / ‘cin’ / ‘cout’ should have prototype.	#include< .h> à header file must be included.
4.	Unknown preprocessor directive.	Uppercase ‘I’ in include should be changed to lowercase ‘i’.
5.	Illegal structure operation.	cin must have >> and cout must have <<
6.	Parameters names are used only with a function body.	[ ] must be used to declare an array and not ( ).
7.	Declaration missing.	Variable must be declared.
8.	L value required.	Proper relational operator must be used (eg == should be used and not = )
9.	Misplaced else.	In ‘if statement’ the action block must be enclosed in { }
10.	Invalid syntax.	‘;’ should not be placed after the condition in if statement / for statement / while / do…while statements.
11.	Switch selection expression must be of integer type.	Switch expression should be evaluated to an integer constant only (char, int).