About preprocessor statement

Replies

• 

  xxxabhash007

  When a pragma is encountered in source code, it overrides the behavior specified by the compiler option.
• 

  anandkumarjha

  vijaymp

  Why #pragma() is used in C programming? What is meant by structure padding in C programming? How is this related to pragma directive? Please do reply.

  _Pragma (and #pragma, which does the same sort of
  thing but with different syntax) has two effects on your
  code.
  We use #pragma or _pragma to tell the compiler something that c language can not express itself:like this function naver returns any value or it does not have any side effect
• 

  Nupin

  #pragma is used to execute a function before main() funtion get executed..
  visit: Coding Tricks: To execute a function before the main() get executed
• 

  Mallory

  macro definitions (#define, #undef)
  
  To define preprocessor macros we can use #define. Its format is:
  #define identifier replacement
  
  When the preprocessor encounters this directive, it replaces any occurrence of identifier in the rest of the code by replacement. This replacement can be an expression, a statement, a block or simply anything. The preprocessor does not understand C++, it simply replaces any occurrence of identifier by replacement.
  
  #define TABLE_SIZE 100int table1[TABLE_SIZE];int table2[TABLE_SIZE];
  After the preprocessor has replaced TABLE_SIZE, the code becomes equivalent to:
  
  int table1[100];int table2[100];
  This use of #define as constant definer is already known by us from previous tutorials, but #define can work also with parameters to define function macros:
  
  #define getmax(a,b) a>b?a:b