Syntax 'trap'

2.1  Function declaration

if (flags & (FLAG != 0) )

2.2 C Language operator priority ： The two most important things to remember are ：

1. Any logical operator has a lower priority than any relational operator

2. The shift operator has a lower priority than the arithmetic operator , But higher than relational operators

Example ：

while (c = getc(in) != EOF)

putc(c, out)

stay while Expression ,c First, the assigned function getc(in) The return value of , then EOF Compare whether the end of the file is reached to determine whether the loop is terminated . however   The assignment operator takes precedence over any comparison operator , so

while ((c = getc(in) ) != EOF)

 putc(c,out)

2.3 Note the semicolon of the statement end flag ;

if(x[i] > y[i]);

big = x[i];

It means nothing has been done , It's already running if (x[i] > y[i]);

 if (x[i] > big)

big = x[i]

  Means to judge , Then the assignment statement is run to execute

 

 if（ n < 3)

 return 

 logrec.date = x[0];

 logrec.time = x[1];

 logrec.code = x[2];

  Here return A semicolon is left behind the statement , However, this code will still pass smoothly , Compile without error ,

 if (n < 3)

 return logrec.date = x[0];

 logrec.time = x[1];

 logrec.code = x[2];

 struct logrec {

 int date;

 int time;

 int code; 

 }

main()

{

...

}