如何在c中转换if切换案例

Question

if(a > b)
{printf("%d is greater than %d", a, b);}
else if( a < b )
{printf("%d is greater than %d", b, a);}
else
{printf("%d is equal to %d", a, b);}

How do I convert an if statement to a switch-case in C? I'm trying, but i don't know the answer to this problem

Answer 1

switch statements are used to test an input expression against a finite set of possible values.

You're trying to compare two variables. This is not a use case for switch .

Your if / else if chain is fine.

Answer 2

switch ((a < b) - (a > b)) {
case -1:
    printf("%d is greater than %d", a, b);
    break;
case 1:
    printf("%d is greater than %d", b, a);
    break;
default:
    printf("%d is equal to %d", a, b);
}

Answer 3

joke :

switch ((a > b) ? 1 : ((a == b) ? 0 : -1)) {
case 1:
  printf("%d is greater than %d", a, b);
  break;
case 0:
  printf("%d is equal to %d", a, b);
  break;
default:
  printf("%d is greater than %d", b, a);
}

Answer 4

You're stumbling on a three way comparison here.

You could write switch ((a < b) - (a > b)) { with -1, 0 and +1 as the case labels for a < b , a == b , and a > b respectively. Note that you need the parentheses since binary - has a higher precedence than < or > .

In C++ that expression has been encapsulated in the three way comparison operator <=> and you could write, simply

switch (a <=> b){

with the case labels as before. As far as I know there is no proposal to include that operator in C.