If statement in C - Step-by-Step Execution

Concept Flow - If statement

Start

↓

Evaluate condition

↓

Condition True?

No→Skip if block

↓

Execute if block

↓

Continue

↓

End

The program checks a condition. If true, it runs the code inside the if block. Otherwise, it skips it and continues.

Execution Sample

C

#include <stdio.h>

int main() {
    int x = 5;
    if (x > 3) {
        printf("x is greater than 3\n");
    }
    return 0;
}

Checks if x is greater than 3 and prints a message if true.

Execution Table

Step	Condition	Result	Branch Taken	Output
1	x > 3	True	Execute if block	x is greater than 3
2	End of if	N/A	Continue

💡 Condition is true, so the if block runs once, then execution continues.

Variable Tracker

Variable	Start	After if	Final
x	5	5	5

Key Moments - 2 Insights

Why does the code inside the if block run only when the condition is true?

Because the if statement checks the condition first (see execution_table step 1). If the condition is true, it runs the block; otherwise, it skips it.

What happens if the condition is false?

The program skips the if block entirely and continues after it, as shown by the 'Skip if block' path in the concept_flow.

Visual Quiz - 3 Questions

Look at the execution table, what is the output at step 1?

A x is less than 3

B No output

C x is greater than 3

D Error

💡 Hint

Check the Output column in execution_table row 1.

At which step does the program decide to skip the if block if the condition is false?

A Step 2

B Step 1

C Before Step 1

D There is no skip step

💡 Hint

Look at the Branch Taken column in execution_table step 1.

If x was 2 instead of 5, what would happen in the execution table?

A Condition would be false and no output

B Program would crash

C Condition would be true and output printed

D Output would be different text

💡 Hint

Refer to the Condition and Output columns in execution_table step 1.

Concept Snapshot

If statement syntax:
if (condition) {
    // code runs if condition is true
}

Checks condition once.
Runs block only if true.
Skips block if false.

Full Transcript

This visual trace shows how an if statement works in C. The program starts and evaluates the condition inside the if. If the condition is true, it executes the code inside the if block, printing a message. If false, it skips the block and continues. The variable x remains unchanged throughout. The execution table shows each step, the condition result, and what branch the program takes. This helps beginners see exactly when and why the if block runs or is skipped.