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Regarding Assertion

 
Ranch Hand
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Can any one tell me why the compiler error in this prg??

class Test {

String f(int i) {
switch(i) {
case 0 : return "A";
case 1 : return "B";
case 2 : return "C";
default : assert false;

}
}
public static void main(String arg[]) {

Test t=new Test();
for(int i=0;i<4;i++) {
System.out.println(t.f(i));
}
}
}
 
Ranch Hand
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Please show that you have made an effort to solve the problem. What does the error message mean to you? What happens if assertions are disabled at runtime?
[ November 27, 2006: Message edited by: Barry Gaunt ]
 
Suguna Gollapally
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I got Compiler error : missing return statement

After i changege the code below :

class Test {

String f(int i) {
switch(i) {
case 0 : return "A";
case 1 : return "B";
case 2 : return "C";
default : assert false;

}
return "s";
}
public static void main(String arg[]) {

Test t=new Test();
for(int i=0;i<4;i++) {
System.out.println(t.f(i));
}
}

compiled fine then enabled assertions : java -ea Test

got the output as
A
B
C
Exception in thread "main" java.lang.AssertionError
at Test.f(Test.java:4586)
at Test.main(Test.java:4595)

But Why Assertion error here ??
 
Greenhorn
Posts: 12
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When i is incremented to 3, the switch statement invokes the default case, which is "assert false". At that point, the assertion test fails, and the program throws a runtime AssertionError.
 
Barry Gaunt
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Think what happens if at compile time assertions are disabled (in Java 5.0 they are enabled by default). Is your program valid when assertions are disabled at compile time?
 
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Suguna,
At compile time compiler checks if u are returning a value. Since the switch may or may not execute compiler forces you to put a rerurn statement. Hence you get an error saying return value required. The error caused is no way related to assertions.
 
Barry Gaunt
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Originally posted by Satish Kota:
Suguna,
At compile time compiler checks if u are returning a value. Since the switch may or may not execute compiler forces you to put a rerurn statement. Hence you get an error saying return value required. The error caused is no way related to assertions.



I was hoping that Suguna was going to work that out.
 
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