What's wrong with this conditional?

Question

I am trying to make a method that tests to see if 3 lengths can make a triangle. I think i'm making some kind of syntax error but i can't figure out what it is.

Here is the relevant bit of code: (its in java)

public static void trya (int a, int b, int c)
{
    if (c>(a+b))
    {
        System.out.println ("yes") ;
    }
    else
    {
        if (b>(a+c)) 
        {
            System.out.println ("yes") ;
        }
    }
    else 
    { 
        if (a>(b+c))
        {
            System.out.println ("yes") ;
        }
    }
    else
    {
        System.out.println ("no") ;
    }

}

this is the error message i get:

tryangle.java:17: 'else' without 'if'
        else 
                ^

Answer 1

You have two else blocks for the first if . Try using else if :

public static void trya (int a, int b, int c)
{
    if (c>(a+b))
    {
        System.out.println ("yes") ;
    }
    else if (b>(a+c)) 
    {
        System.out.println ("yes") ;
    }
    else if (a>(b+c))
    {
        System.out.println ("yes") ;
    }
    else
    {
        System.out.println ("no") ;
    }
}

Answer 2

当你还是学生时，我认为我可能会指出Java在线文档的控制流语句部分。

Answer 3

This is invalid:

if (cond A) {
    // ...
} else {
    if (cond B) {
        // ...
    }
} else {
    if (cond C) {
        // ...
    }
}

It should rather be:

if (cond A) {
    // ...
} else if (cond B) {
    // ...
} else if (cond C) {
    // ...
}

Learn more at this Sun tutorial .

Answer 4

Personally, I don't like if/else very much.

public static boolean isValidTriangle(int a, int b, int c)
{
    return (c > a + b) || (b > a + c) || (a > b + c);
}

public static void trya(int a, int b, int c)
{
    System.out.println(isValidTriangle(a, b, c) ? "yes" : "no");
}

Answer 5

It should be:

public static void trya (int a, int b, int c) 
{ 
    if (c>(a+b)) 
    { 
        System.out.println ("yes") ; 
    } 
    else if (b>(a+c))  
    { 
        System.out.println ("yes") ; 
    } 
    else  if (a>(b+c)) 
    { 
        System.out.println ("yes") ; 
    } 
    else 
    { 
        System.out.println ("no") ; 
    } 
} 

Answer 6

This is how your code is formatted:

if (...) {...}
else {...}
else {...} //else than what?

Answer 7

It may also be worth pointing out that your method doesn't actually test to see if three lengths can make a triangle. For example, trya(1, 1, 4) will result in printing yes even though the side lengths 1, 1, 4 do not form a triangle.

Answer 8

You can't have two else s for the same if. Change your nesting so that you use else if rather than

else
{
    if

Answer 9

看起来问题是你有多个else块，一个if语句只能有一个else块。