text: Create a boolean array " prime [ 0 . . n ] " and initialize all the entries as true . A value in prime [ i ] will finally be false if ' i ' is Not a prime , else true .
code: memset ( prime , true , sizeof ( prime ) ) ; memset ( sum , 0 , sizeof ( sum ) ) ; prime [ 1 ] = false ; for ( int p = 2 ; p * p <= MAX ; p ++ ) {