A simple question for the C language

It's nonsense to say so much above. Landlord please see: pay attention to your program: printf("%d,%d",(a,b),(b,a);

To tell you, (a,b) is the parenthesis operation in C, and its value is the rightmost value of the parentheses, which has nothing to do with the previous ones, for example, (3,4,5,6,7,8) has a value of 8The printf statement in your program prints values b and a, so it's 4 and 3.

if printf("%d,%d",a,b); Then the values are 3 and 4.

I just learned to play C language, and I was asked if there was anything I didn't understand.

To put it simply.

That is, the value of the comma expression is the value of the last expression!!

a=3,b=4,execute "printf("%d,%d",(a,b),(b,a));

a, b) and (b, a) This is a comma expression test, the value of the comma expression is the value of the number after the last comma, for example, (a, b) the value of the last comma is b, and the value of (a, b) is the value of b 4

Comma operator" , "It is enclosed in parentheses, and its rules of operation are the same as normal operations, but the result is the value of the last expression, e.g. a=(3,5,6,7) The result is a=7In e.g. a=(24,89,45); Result a=45;

looking at a=(4,a=10,a+4); The result is a=14;

Do you write like this to work, what do you want to do, what kind of result do you want to get.

You don't set the straight of A and the straight of B to subtract or add, you only give A and B a and B a straight, of course, only show the result of A and B! ''If you add.

a=3,b=4,c;

c=a+b;

printf(“%d,%d”,c);

This way you can show a 3+4 straight!

The comma operator knows no???

The general forms of comma expressions are: Expression 1, Expression 2, Expression 3, ......Expression n

The process of solving a comma expression is to calculate the value of expression 1 first, and then the value of expression 2 ,......Evaluates all the way up to the value of expression n. Finally, the value of the entire comma expression is the value of the expression n.

Take a look at a few examples:

x=8*2, x*4 * the value of the whole expression is 64, and the value of x is 16*

x=8*2, x*4), x*2 * the value of the whole expression is 128, and the value of x is 16*

x=(z=5,5*2) *The whole expression is an assignment expression, its value is 10, and the value of z is 5*

x=z=5,5*2 * The whole expression is a comma expression, it has a value of 10, and both x and z have a value of 5*

Comma expressions are not used much, and are usually only used when assigning initial values to cyclic variables. Therefore, not all commas in the program should be regarded as comma operators, especially when the function is called, and the parameters are separated by commas, so the comma is not a comma operator.

This is the question about comma expressions.

a, b) is a

b, a) is b

In general, for (Expression 1, Expression 2,......The result of expression n) is the result of expression n.

So your output is 4 and 3 respectively