This C tutorial explains how to use the #define preprocessor directive in the C language. In the C Programming Language, the #define directive allows the definition of macros within your source code. These macro definitions allow constant values to be declared for use throughout your code. Macro definitions are not variables and cannot be changed by your program code like variables.
Price Ceilings. If the price ceiling is above the market price, then there is no direct effect. If the price ceiling is set below the market price, then a shortage is created; the quantity demanded will exceed the quantity supplied. The shortage may be resolved in many ways.
Price ceilings, which prevent prices from exceeding a certain maximum, cause shortages. Price floors, which prohibit prices below a certain minimum, cause surpluses, at least for a time. Suppose that the supply and demand for wheat flour are balanced at the current price, and that the government then fixes a lower maximum price. The supply of flour will decrease, but the demand for it will increase.