Check out example codes for "assert() in c". It will help you in understanding the concepts better.

Code Example 1

(Assert Truth of Expression) In the C Programming Language,
assert is a macro that is designed to be used like a function.

Following is syntax for assertion:
			void assert( int expression ); 
Case I  : WHEN expression EVALUATES true,
		  nothing happens and the compiler proceeds to execute successive
Case II : WHEN expression EVALUATES false,
	      the expression, sourcecode filename, and line number are 
          sent to the standard error, and then abort() function is called.

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