CODEWITHSUNDEEP
javaif-statementvariablesdouble
seen20
seen20

Reputation: 29

how to put multiple variables in if statement in java?

I'm super new to programming , I'm making a program to calculate If two lines are parallel or not, the lines are considered parallel if a1 b2 = a2 b1 but I don't know how to put multiple variables in one if statement I have searched but I didn't find the answer can you help me please?

if (a1 && b2 == a2 && b1)
    System.out.print("the lines are parallel");
else System.out.print("the lines are not parallel");

Upvotes: 1

Views: 820

Answers (4)

ProgrammingEnthusiast
ProgrammingEnthusiast

Reputation: 480

You can do write the if statement as follows:

if((a1==b2)&&(a2==b1))

Upvotes: 0

rzwitserloot
rzwitserloot

Reputation: 103018

What does a1 b2 = a2 b1 mean?

It means: If a1 multiplied by b2 equals a2 multiplied by b1

Then program that: a1 * b2 == a2 * b1. The habit of assuming 'multiply' when you put entries right next to each other is a math thing. In java that does not work; If you want to multiply, * is what you want.

It means: if a1 equals b2, and a2 equals b1

Then program that: && is 'and', as in, given two true/false values, you can use the && operator to reduce them to a single true/false value (true if both are true, false otherwise). Just like 5 + 7 reduces two numbers to one number, true && false does the same. Thus, you can't use && as "and" in the sense of "if a and b are equal to c" (because 'a' is not a true/false value). Thus:

(a1 == b2) && (b1 == a2)

Etcetera

You get the gist - between == and && and perhaps some parentheses, you can do this.

Upvotes: 2

null_awe
null_awe

Reputation: 483

If you want parallel lines all you need is if (a1 == a2), the b1 and b2 don't matter.

However, if you want to check if the numbers multiplied together are equal use:

if ((a1 * b1) == (a2 * b2)) System.out.print("the lines are parallel");

and the compiler will calculate the expressions inside the parenthesis first before checking for equality.

Upvotes: 1

qubix00n
qubix00n

Reputation: 157

If your line equation is y = ax + b then lines are parallel if a1 == a2 so your 'if statement' should be if (a1 == a2).

Upvotes: 2

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