Relational operators in C - Step-by-Step Execution

Concept Flow - Relational operators

Start

↓

Evaluate operands

↓

Apply relational operator

↓

Result: true (1) or false (0)

↓

Use result in expression or decision

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End

Relational operators compare two values and return 1 if true or 0 if false, which can be used in decisions.

Execution Sample

C

int a = 5;
int b = 3;
int result = a > b;
printf("%d", result);

Compares if a is greater than b and prints 1 if true, 0 if false.

Execution Table

Step	Expression	Operands	Evaluation	Result	Output
1	a > b	a=5, b=3	5 > 3	true (1)	1
2	End	-	-	-	-

💡 Program ends after printing the result of the relational comparison.

Variable Tracker

Variable	Start	After Step 1	Final
a	5	5	5
b	3	3	3
result	undefined	1	1

Key Moments - 2 Insights

Why does the relational operator return 1 or 0 instead of true or false?

In C, relational operators return integer 1 for true and 0 for false, as shown in execution_table step 1, because C uses integers to represent boolean values.

What happens if both operands are equal with the '>' operator?

If operands are equal, the '>' operator returns 0 (false), because the condition is not true. This would be seen in execution_table if a and b were equal.

Visual Quiz - 3 Questions

Look at the execution table, what is the value of 'result' after step 1?

A 1

B 0

C 5

D 3

💡 Hint

Check the 'Result' column in execution_table row 1.

At which step does the program print the output?

A Step 2

B Before Step 1

C Step 1

D No output is printed

💡 Hint

Look at the 'Output' column in execution_table row 1.

If 'a' was 2 and 'b' was 3, what would 'result' be after step 1?

A 1

B 0

C 2

D 3

💡 Hint

Relational operator '>' returns 1 if left operand is greater, else 0.

Concept Snapshot

Relational operators compare two values.
Operators: >, <, >=, <=, ==, !=
Return 1 if true, 0 if false.
Used in conditions and expressions.
Example: int r = a > b; // r is 1 if a > b else 0

Full Transcript

This lesson shows how relational operators work in C. They compare two values and return 1 if the comparison is true or 0 if false. For example, 'a > b' checks if a is greater than b. If a is 5 and b is 3, 'a > b' is true, so the result is 1. This result can be stored in a variable or used in decisions like if statements. The execution table traces the comparison step by step, showing operands, evaluation, and output. Variables a and b keep their values, while result stores the comparison outcome. Beginners often wonder why the result is 1 or 0 instead of true or false; in C, 1 and 0 represent true and false respectively. Another common question is what happens if values are equal; the operator returns 0 because the condition is false. The quiz asks about the result value, when output is printed, and what happens if values change. Remember, relational operators are essential for making decisions in programs.