Values, Types, and Expressions

Operators

Combine values with arithmetic, comparison, and logic.

operators Arithmetic operators compute numbers, `%` gives a remainder, comparisons yield booleans, and `&&` combines boolean conditions.

Operators

a
operators.js
Replay: real traced execution (multi-file project)
const a = 7;
const b = 3;
const sum = a + b;
const remainder = a % b;
const isBig = a > b && sum > 5;

console.log("sum=" + sum);
console.log("remainder=" + remainder);
console.log("isBig=" + isBig);

const a = 4;
const b = 3;
const sum = a + b;
const remainder = a % b;
const isBig = a > b && sum > 5;

console.log("sum=" + sum);
console.log("remainder=" + remainder);
console.log("isBig=" + isBig);

const a = 12;
const b = 3;
const sum = a + b;
const remainder = a % b;
const isBig = a > b && sum > 5;

console.log("sum=" + sum);
console.log("remainder=" + remainder);
console.log("isBig=" + isBig);

  1. a ← 7, b ← 3, sum ← 10, remainder ← 1, isBig ← true

    1const a→ 7 = 7; //@a=4, 122const b→ 3 = 3;3const sum→ 10 = a→ 7 + b3;4const remainder→ 1 = a→ 7 % b3;5const isBig→ true = a→ 7 > b→ 3 && sum→ 10 > 5;67console.log("sum=" + sum10);8console.log("remainder=" + remainder1);9console.log("isBig=" + isBigtrue);
    outputsum=10
remainder=1
isBig=true

  1. a ← 4, b ← 3, sum ← 7, remainder ← 1, isBig ← true

    1const a→ 4 = 4;2const b→ 3 = 3;3const sum→ 7 = a→ 4 + b3;4const remainder→ 1 = a→ 4 % b3;5const isBig→ true = a→ 4 > b→ 3 && sum→ 7 > 5;67console.log("sum=" + sum7);8console.log("remainder=" + remainder1);9console.log("isBig=" + isBigtrue);
    outputsum=7
remainder=1
isBig=true

  1. a ← 12, b ← 3, sum ← 15, remainder ← 0, isBig ← true

    1const a→ 12 = 12;2const b→ 3 = 3;3const sum→ 15 = a→ 12 + b3;4const remainder→ 0 = a→ 12 % b3;5const isBig→ true = a→ 12 > b→ 3 && sum→ 15 > 5;67console.log("sum=" + sum15);8console.log("remainder=" + remainder0);9console.log("isBig=" + isBigtrue);
    outputsum=15
remainder=0
isBig=true

Follow the Operators

  1. a starts at 7.
  2. b is 3.
  3. sum = a + b becomes 10.
  4. remainder = a % b becomes 1.
  5. isBig becomes true, so the program prints sum=10, remainder=1, and isBig=true. | a | b | sum | remainder | isBig | | --- | --- | --- | --- | --- | | 4 | 3 | 7 | 1 | true | | 7 | 3 | 10 | 1 | true | | 12 | 3 | 15 | 0 | true |

Exercise: operators.js

Reproduce sum=10 and remainder=1, then use the pinned a values 4 and 12 to predict each row.