Goto statement overview in C - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to jump to the label using goto.

C

int main() {
    int x = 0;
    if (x == 0) {
        [1] skip;
    }
    printf("This will be skipped.\n");
    skip:
    printf("Jumped to label.\n");
    return 0;
}

Drag options to blanks, or click blank then click option'

Acontinue

Bjump

Cbreak

Dgoto

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'jump' instead of 'goto'.

Using 'break' or 'continue' outside loops.

The goto statement is used to jump to a labeled statement in C.

2fill in blank

medium

Complete the code to define a label named 'end'.

C

int main() {
    int i = 5;
    if (i > 0) {
        printf("i is positive\n");
    }
    [1]
    return 0;
}

Drag options to blanks, or click blank then click option'

Aend:

Bend;

Cend

Dlabel

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting the colon after the label name.

Adding a semicolon after the label.

Labels in C end with a colon, like end:.

3fill in blank

hard

Fix the error in the goto statement to jump to label 'start'.

C

int main() {
    [1];
    printf("At start label\n");
    return 0;
    start:
    printf("This is the start label.\n");
}

Drag options to blanks, or click blank then click option'

Agoto start

Bgoto start;

Cgoto start:

Dgoto; start

Attempts:

3 left

💡 Hint

Common Mistakes

Adding a colon after the label name in goto.

Using incorrect punctuation.

The correct syntax for goto is goto label_name; with a semicolon after the statement.

4fill in blank

hard

Complete the code to create a loop using goto and label.

C

int main() {
    int count = 0;
    loop_start:
    if (count < 3) {
        printf("Count: %d\n", count);
        count++;
        [1] loop_start;
    }
    return 0;
}

Drag options to blanks, or click blank then click option'

A:

Bgoto

C;

D,

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting the colon after the label.

Using incorrect syntax for goto.

The label must end with a colon, and the goto statement jumps to that label.

5fill in blank

hard

Fill all three blanks to use goto to skip printing 'Skipped' and jump to 'end' label.

C

int main() {
    int x = 1;
    if (x == 1) [1] end;
    printf("Skipped\n");
    [2]:
    printf("After label\n");
    return 0;
    [3]:
}

Drag options to blanks, or click blank then click option'

Agoto

Bend

Dstart

Attempts:

3 left

💡 Hint

Common Mistakes

Using label names without colons.

Using incorrect label names.

Use goto end; to jump to the label end:. The label start: is unused here.

Practice

1. What does the goto statement do in C programming?

easy

A. It jumps to a labeled part of the code within the same function.

B. It creates a new function.

C. It declares a variable.

D. It ends the program immediately.

Solution

1. Step 1: Understand the purpose of goto

   The goto statement is used to jump to a specific label inside the same function.

2. Step 2: Compare with other options

   Other options describe unrelated actions like creating functions or ending programs, which goto does not do.

3. Final Answer:

   It jumps to a labeled part of the code within the same function. -> Option A

4. Quick Check:

   goto jumps to label [OK]

Hint: Remember: goto jumps only inside the same function [OK]

Common Mistakes:

• Thinking goto can jump between functions
• Confusing goto with function calls
• Believing goto ends the program

2. Which of the following is the correct syntax to use goto in C?

easy

A. goto: label_name;

B. goto(label_name);

C. goto label_name;

D. goto = label_name;

Solution

1. Step 1: Recall correct goto syntax

   The correct syntax is simply goto label_name; without parentheses or equals sign.

2. Step 2: Check other options for syntax errors

   The other options use invalid syntax: one with a colon after goto, one with parentheses, and one with an equals sign.

3. Final Answer:

   goto label_name; -> Option C

4. Quick Check:

   Correct syntax is goto label; [OK]

Hint: Use 'goto label;' without parentheses or equals [OK]

Common Mistakes:

• Adding parentheses after goto
• Using equals sign with goto
• Writing colon after goto

3. What will be the output of this C code?

int main() {
    int x = 0;
    start:
    x++;
    if (x < 3) goto start;
    printf("%d", x);
    return 0;
}

medium

A. 3

B. 0

C. 1

D. Infinite loop

Solution

1. Step 1: Trace the loop with goto

   The label start is before x++. The code increments x, then checks if x < 3. If yes, it jumps back to start.

2. Step 2: Count increments until condition fails

   x starts at 0, increments to 1, 2, then 3. When x is 3, condition x < 3 is false, so it stops looping and prints 3.

3. Final Answer:

   3 -> Option A

4. Quick Check:

   Loop increments x to 3 before printing [OK]

Hint: Count increments until condition fails [OK]

Common Mistakes:

• Thinking it prints 0 or 1
• Assuming infinite loop without checking condition
• Confusing label position

4. Identify the error in this C code using goto:

int main() {
    goto end;
    printf("Hello");
    end:
    return 0;
}

medium

A. Cannot jump over variable declarations.

B. No error; code runs and prints nothing.

C. Label 'end' is not defined.

D. Syntax error in goto statement.

Solution

1. Step 1: Check label definition and usage

   The label end is defined after the goto statement, so jumping to it is valid.

2. Step 2: Analyze program flow

   The program jumps to end, skipping the printf. So it prints nothing and returns 0 without error.

3. Final Answer:

   No error; code runs and prints nothing. -> Option B

4. Quick Check:

   Jumping to label after goto is allowed [OK]

Hint: Jumping forward to label is allowed; no error [OK]

Common Mistakes:

• Thinking label must be before goto
• Expecting output when skipped
• Assuming syntax error in goto

5. How can goto be used to break out of nested loops in C? Choose the best example.

hard

A. Use goto to jump to a label inside the inner loop.

B. Use goto to jump to a label after both loops finish.

C. Use goto to restart the inner loop from the beginning.

D. Use goto inside inner loop to jump to a label outside both loops.

Solution

1. Step 1: Understand nested loops and breaking out

   Normally, break exits only one loop. To exit multiple loops, goto can jump to a label after all loops.

2. Step 2: Identify correct usage of goto

   Using goto inside the inner loop to jump outside both loops immediately breaks out of all loops.

3. Final Answer:

   Use goto inside inner loop to jump to a label outside both loops. -> Option D

4. Quick Check:

   Goto jumps out of nested loops [OK]

Hint: Use goto to jump outside nested loops for quick exit [OK]

Common Mistakes:

• Using goto to restart loops instead of exit
• Jumping to label inside loops only
• Thinking break exits all loops