C goto Statement

goto jumps straight to another spot in the code marked by a label, like skipping to a different page of a book. It can make code hard to follow, so it is used sparingly.

In this page:

What is goto?
Syntax and Labels
Breaking Out of Deep Nesting
Backward Jumps
Best Practices with goto

Syntax

goto label;
// ... skipped code ...
label:
    statement;

What is goto?

goto transfers execution directly to a labeled line elsewhere in the same function, bypassing the normal sequential flow of the code entirely, which makes it powerful but also the control-flow tool most likely to make a program's logic hard to follow if used carelessly.

Example: What is goto?

// Include standard input/output (printf, scanf)
#include <stdio.h>
// Program execution starts in main()
int main() {
	goto skip;
	// Print formatted text to the screen
	printf("never runs");
	skip:
	printf("Jumped past the printf");
	// Return 0 to signal that the program finished successfully
	return 0;
}

Syntax and Labels

A label is simply an identifier followed by a colon placed in front of a statement, marking that line as a valid jump target, and it can be positioned anywhere within the same function that a goto elsewhere in that function wants to reach.

Example: Syntax and Labels

// Include standard input/output (printf, scanf)
#include <stdio.h>
// Program execution starts in main()
int main() {
	// Declare x and set it to 5
	int x = 5;
	if (x > 0) goto positive;
	// Print formatted text to the screen
	printf("not positive");
	// Return 0 to signal that the program finished successfully
	return 0;
	positive:
	printf("Positive");
	// Return 0 to signal that the program finished successfully
	return 0;
}

Breaking Out of Deep Nesting

When an error condition is detected deep inside several nested loops, a single goto cleanup; can exit all of them in one step, whereas a plain break only escapes the single innermost loop, leaving you to manually break out of each remaining level.

Example: Breaking Out of Deep Nesting

// Include standard input/output (printf, scanf)
#include <stdio.h>
// Program execution starts in main()
int main() {
	// Loop: repeat while the condition holds
	for (int i = 0; i < 3; i++) {
		// Loop: repeat while the condition holds
		for (int j = 0; j < 3; j++) {
			// Check whether i == 1 && j == 1
			if (i == 1 && j == 1) {
				goto cleanup;
			}
		}
	}
	cleanup:
	printf("Exited both loops");
	// Return 0 to signal that the program finished successfully
	return 0;
}

Backward Jumps

Because goto can jump to a label that appears earlier in the code, it's possible to build a loop by jumping backward to a label — but you must make sure the surrounding condition eventually evaluates false, or that backward jump repeats forever exactly like a runaway while loop.

Example: Backward Jumps

// Include standard input/output (printf, scanf)
#include <stdio.h>
// Program execution starts in main()
int main() {
	// Declare i and set it to 0
	int i = 0;
	loopStart:
	if (i < 3) {
		// Print formatted text to the screen
		printf("%d ", i);
		i++;
		goto loopStart;
	}
	// Return 0 to signal that the program finished successfully
	return 0;
}

Best Practices with goto

Most C style guides restrict goto to a narrow set of legitimate uses, chiefly escaping deeply nested loops and centralizing cleanup code (like closing several open resources before returning), while steering clear of using it as a general substitute for structured loops and conditionals.

Example: Best Practices with goto

// Include standard input/output (printf, scanf)
#include <stdio.h>
// Program execution starts in main()
int main() {
	// Declare success and set it to 0
	int success = 0;
	// Check whether !success
	if (!success) {
		goto cleanup;
	}
	// Print formatted text to the screen
	printf("never runs");
	cleanup:
	printf("Centralized cleanup reached");
	// Return 0 to signal that the program finished successfully
	return 0;
}

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