Switch statement - Step-by-Step Execution

Concept Flow - Switch statement

Start

↓

Evaluate expression

↓

Match case?

No→Default case?

↓

Execute case

↓

Break?

No→Continue next case

Yes↓

Exit switch

The switch statement evaluates an expression, matches it to a case, executes that case's code, and exits or continues based on break statements.

Execution Sample

C

int x = 2;
switch (x) {
  case 1:
    printf("One\n");
    break;
  case 2:
    printf("Two\n");
    break;
  default:
    printf("Other\n");
}

This code checks the value of x and prints the matching case text.

Execution Table

Step	Expression Value	Case Checked	Match?	Action	Output
1	2	case 1	No	Skip case 1
2	2	case 2	Yes	Execute case 2 code	Two
3	2	break	N/A	Exit switch

💡 Break statement after case 2 causes exit from switch.

Variable Tracker

Variable	Start	After Step 1	After Step 2	Final
x	2	2	2	2

Key Moments - 2 Insights

Why does the switch stop after printing "Two"?

Because of the break statement at step 3 in the execution_table, which exits the switch to prevent running other cases.

What happens if there is no break after a case?

The switch continues to execute the next case(s) until it finds a break or reaches the end, as shown by the 'Continue next case' path in the concept_flow.

Visual Quiz - 3 Questions

Look at the execution_table, what is the output at step 2?

A One

B Two

C Other

D No output

💡 Hint

Check the 'Output' column at step 2 in the execution_table.

At which step does the switch statement exit?

A Step 1

B Step 2

C Step 3

D It never exits

💡 Hint

Look at the 'Action' column and see when 'Exit switch' happens.

If the break at step 3 was removed, what would happen?

A Only case 2 runs

B Default case runs after case 2

C Program crashes

D No output at all

💡 Hint

Refer to the concept_flow where 'No break' leads to 'Continue next case'.

Concept Snapshot

switch(expression) {
  case value1:
    // code
    break;
  case value2:
    // code
    break;
  default:
    // code
}

- Evaluates expression once
- Matches cases in order
- Executes matching case
- break exits switch
- Without break, runs next cases

Full Transcript

The switch statement in C evaluates an expression and compares it to each case value. If a match is found, it executes that case's code. The break statement stops further case execution and exits the switch. Without break, execution continues to the next case. If no case matches, the default case runs if present. This example shows x=2 matching case 2, printing 'Two', then breaking to exit.