goto Statement in C Language with Examples

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Introduction:

We have looked at the while loop, for loop, and do while loop in our earlier articles. In today’s article, We will look at the goto statement in C language with example programs. We also look at when to use and when to avoid the goto statement with examples and detailed explanations.

The goto statement in C language:

The goto statement is an un-conditional control statement in C.

The goto statement is used to jump from one statement to another statement (which is prefixed with the label) inside any function. goto is used to iterate over a code block.

📢 goto Statement is also called the jump statement.

Goto Statement can be used to

  • Repeat a code block
  • Break loops ( We can also break out of Nested Loops)

The goto statement must be used inside of a single function. The goto statement cannot be distributed among several functions.

📢 The goto statement must be used within the single function.

The goto is avoided since it makes the program more complex and difficult to read. Since we can accomplish the majority of these scenarios with C-Language Loops, it is not advisable to use the goto statement, Except in the cases where we absolutely need the goto statement. Like if you want to break out of nested loops.

Syntax of goto statement in C:

We have two different syntaxes for the goto statements.

C goto syntax 1:

C goto Syntax 2:

Here the LABEL is an Identifier, you can use any valid Identifier here. Make sure you follow the Identifiers naming rules.

Whenever the compiler comes across the goto statement, It will look for the LABEL and transfer the program control to LABEL: statement. This way we can jump from one statement in the function to another statement.

To understand the goto statement better, let’s have a look at an example program.

Flow Diagram of goto statement in C Language:

goto-statement-in-c-language-flow

Program to understand the goto statement in C Programming:

Let’s write a program to print the multiplication table for the user-provided number using the goto statement.

Here we are going to use the goto to repeat a code block. We can achieve the same thing using the C Loops as well. but let’s try it with the break statement.

Example Program: Print Multiplication table using the goto statement:

Program Output:

Multiplication Table Program Explanation:

As you can see from the above output, we have used the goto PRODUCT; and PRODUCT: to iterate over the code block. It is like a C Loop.

We used a counter variable to track the number of iterations. At each iteration, we printed the multiplication table entry.

The goto Statement with multiple functions in C:

As we have mentioned earlier, The goto statement can’t spread across multiple functions. which results in the compilation error.

Let’s look at an example program, where we will have the goto LABEL; in one function and LABEL: Identifier in another function.

Multi-function goto statement example:

Program Output:

As you can see from the above output, We got the error error: label MUTLIFUNCTION used but not defined , As the goto statement works within the single function, The compiler is not able to find the MULTIFUNCTION label inside the main function. So compiler generated the error message.

📢 The goto statement only works within a single function.

Why avoid the goto statement?

Because if you have nested goto statements or multiple goto statements, Then we might end up with Infinite loops.

We have discussed about the infinite loops in c in the following article

Please have a look at the following program.

Infinite loops due to multiple goto statements:

Program Output:

Multiple goto statements program Explanation:

We have used two goto statements in the above program. and we used them in a such way that they are going to execute forever. which caused the infinite loop.

So we need to be careful while using multiple or nested goto statements to avoid unnecessary bugs.

📢 It is recommended to avoid nested or multiple goto statements, which reduce the code readability and may cause unexpected bugs.

When to use the goto statement in C – To Break out of Nested Loops:

There will be a situation where you want to break out the nested loops, Then you can use the goto statement to jump out of all loops.

If you the break statement in a nested loop, Only the InnerMost loop will be terminated. So we can use the goto statement to break out of all loops.

Here is an example program.

Break out of all Nested loops using goto statement:

Program Output:

As you can see from the above output, Two nested loops are terminated once j reached 5. Here we used the goto statement to terminate all loops. Unlike the break statement, goto terminates the loops based on the label, Here we specified the label ( OUT ) outside of the nested loops.

As soon as the goto OUT; was executed, The program control came out of both loops and reached OUT: statement.

The goto statement will be appropriate in a lot of other places. Please only use it when necessary.

Conclusion:

In this article, We have learned about the goto statement in the C Programming language. We looked at when to use the goto statement and when not to use the goto statement. Finally, we looked at the nested loops with goto statement.

C Tutorials Index:

C Loops Practice programs:

Venkat

Hi Guys, I am Venkatesh. I am a programmer and an Open Source enthusiast. I write about programming and technology on this blog.

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