220214c language learning diary

One , Logical operators

&& and ||

Be careful , They are binocular operators , Cannot be used as

        a && b && c

or a || b || c

Two ,switch and break

switch It can be used to replace some In the same if There are statement blocks with different results

Such as ：if（a = 0)

puts(" frigging awesome ");

if (a = 1)

puts(" Horseshoe ")

if (a = 2)

puts(" People force ")

It can be replaced by ：

switch(a){

case 0 : puts(" frigging awesome "); break;

case 1 : puts(" Horseshoe "); break;

case 2 : puts(" People force "); break;

default : puts(" Please enter 0 or 1 or 2, There is no other force .”）

}

It can make the statement more concise , Easy to read .

Blue (a)： yes switch Expression of function , Remember to follow the curly braces to indicate the scope

purple case 0： yes “ label ”, This number is an expression (a) Results in . in addition ,case There must be a space before the next number .

gray default： When the expected value is not entered , Automatically run this statement .

Add , Don't forget it. case Add... At the end of the statement break; Otherwise, the program will be executed automatically when it runs break The next statement after .