Which of the following lines would generate a compile time error when placed in a main method?

Compile-Time Errors: Errors that occur when you violate the rules of writing syntax are known as Compile-Time errors. This compiler error indicates something that must be fixed before the code can be compiled. All these errors are detected by the compiler and thus are known as compile-time errors. Most frequent Compile-Time errors are:

Missing Parenthesis (})
Printing the value of variable without declaring it
Missing semicolon (terminator)

Below is an example to demonstrate Compile-Time Error:

Error:

error: expected ';' before '}' token

Run-Time Errors: Errors which occur during program execution(run-time) after successful compilation are called run-time errors. One of the most common run-time error is division by zero also known as Division error. These types of error are hard to find as the compiler doesn’t point to the line at which the error occurs.For more understanding run the example given below.

cout <<"result = " << div;

printf("result = %d", div);

Error:

warning: division by zero [-Wdiv-by-zero] div = n/0;

In the given example, there is Division by zero error. This is an example of run-time error i.e errors occurring while running the program.
The Differences between Compile-Time and Run-Time Error are:

Compile-Time Errors	Runtime-Errors
These are the syntax errors which are detected by the compiler.	These are the errors which are not detected by the compiler and produce wrong results.
They prevent the code from running as it detects some syntax errors.	They prevent the code from complete execution.
It includes syntax errors such as missing of semicolon(;), misspelling of keywords and identifiers etc.	It includes errors such as dividing a number by zero, finding square root of a negative number etc.

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Error is an illegal operation performed by the user which results in the abnormal working of the program. Programming errors often remain undetected until the program is compiled or executed. Some of the errors inhibit the program from getting compiled or executed. Thus errors should be removed before compiling and executing.

The most common errors can be broadly classified as follows:

1. Run Time Error:

Run Time errors occur or we can say, are detected during the execution of the program. Sometimes these are discovered when the user enters an invalid data or data which is not relevant. Runtime errors occur when a program does not contain any syntax errors but asks the computer to do something that the computer is unable to reliably do. During compilation, the compiler has no technique to detect these kinds of errors. It is the JVM (Java Virtual Machine) that detects it while the program is running. To handle the error during the run time we can put our error code inside the try block and catch the error inside the catch block.

For example: if the user inputs a data of string format when the computer is expecting an integer, there will be a runtime error. Example 1: Runtime Error caused by dividing by zero

public static void main(String args[])

Runtime Error in java code:

Exception in thread "main" java.lang.ArithmeticException: / by zero at DivByZero.main(File.java:14)

Example 2: Runtime Error caused by Assigning/Retrieving Value from an array using an index which is greater than the size of the array

public static void main(String args[])

System.out.println("Value assigned! ");

RunTime Error in java code:

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 9 at RTErrorDemo.main(File.java:10)

2. Compile Time Error:

Compile Time Errors are those errors which prevent the code from running because of an incorrect syntax such as a missing semicolon at the end of a statement or a missing bracket, class not found, etc. These errors are detected by the java compiler and an error message is displayed on the screen while compiling. Compile Time Errors are sometimes also referred to as Syntax errors. These kind of errors are easy to spot and rectify because the java compiler finds them for you. The compiler will tell you which piece of code in the program got in trouble and its best guess as to what you did wrong. Usually, the compiler indicates the exact line where the error is, or sometimes the line just before it, however, if the problem is with incorrectly nested braces, the actual error may be at the beginning of the block. In effect, syntax errors represent grammatical errors in the use of the programming language.

Example 1: Misspelled variable name or method names

public static void main(String args[])

Compilation Error in java code:

prog.java:14: error: cannot find symbol + sum); ^ symbol: variable sum location: class MisspelledVar 1 error

Example 2: Missing semicolons

public static void main(String args[])

String s = "GeeksforGeeks";

System.out.println("Welcome to " + s)

Compilation Error in java code:

prog.java:8: error: ';' expected System.out.println("Welcome to " + s) ^ 1 error

Example: Missing parenthesis, square brackets, or curly braces

class MissingParenthesis {

public static void main(String args[])

System.out.println("Printing 1 to 5 \n");

for (i = 1; i <= 5; i++ {

System.out.println(i + "\n");

Compilation Error in java code:

prog.java:10: error: ')' expected for (i = 1; i <= 5; i++ { ^ 1 error

Example: Incorrect format of selection statements or loops

public static void main(String args[])

System.out.println("Multiplication Table of 7");

for (i = 1, i <= 10; i++) {

System.out.println(ans + "\n");

Compilation Error in java code:

prog.java:12: error: not a statement for (i = 1, i <= 10; i++) { ^ prog.java:12: error: ';' expected for (i = 1, i <= 10; i++) { ^ 2 errors

Logical Error: A logic error is when your program compiles and executes, but does the wrong thing or returns an incorrect result or no output when it should be returning an output. These errors are detected neither by the compiler nor by JVM. The Java system has no idea what your program is supposed to do, so it provides no additional information to help you find the error. Logical errors are also called Semantic Errors. These errors are caused due to an incorrect idea or concept used by a programmer while coding. Syntax errors are grammatical errors whereas, logical errors are errors arising out of an incorrect meaning. For example, if a programmer accidentally adds two variables when he or she meant to divide them, the program will give no error and will execute successfully but with an incorrect result.

Example: Accidentally using an incorrect operator on the variables to perform an operation (Using ‘/’ operator to get the modulus instead using ‘%’)

public class LErrorDemo {

public static void main(String[] args)

System.out.println("Reversed number is "

Output: Reversed number is 7870

Example: Displaying the wrong message

public static void main(String args[])

"Finding the largest number \n");

a + " is the largest Number");

b + " is the smallest Number");

c + " is the largest Number");

Output: Finding the largest number 8 is the smallest Number

Syntax Error:

Syntax and Logical errors are faced by Programmers.

Spelling or grammatical mistakes are syntax errors, for example, using an uninitialized variable, using an undefined variable, etc., missing a semicolon, etc.

int x, y; x = 10 // missing semicolon (;) z = x + y; // z is undefined, y in uninitialized.

Syntax errors can be removed with the help of the compiler.

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