Question

How to implement a cumulative sum of numbers in an int array in JavaScript

Answer 1

// 0 : 0+1=1 : 0+1+2=3 : 0+1+2+3=6 : 0+1+2+3+4=10 : 0+1+2+3+4+5=15 ...

const arr = [0, 1, 2, 3, 4, 5, 6]; 

let cumulativeSum = []
let sum = 0;

arr.map((e) => {
      sum = sum + e;
      cumulativeSum.push(sum);
})

console.log(cumulativeSum);


 
/*
run:
 
[0, 1, 3, 6, 10, 15, 21]
 
*/

 

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Answer 2

const arr = [0, 1, 2, 3, 4, 5, 6]; 

let cumulativeSum = []
let sum = 0;

arr.forEach((e) => {
      sum = sum + e;
      cumulativeSum.push(sum);
})

console.log(cumulativeSum);

 
/*
run:
 
[0, 1, 3, 6, 10, 15, 21]
 
*/

 

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Answer 3

const cumulativeSum = (sum => value => sum += value)(0);

const arr = [0, 1, 2, 3, 4, 5, 6]; 

console.log(arr.map(cumulativeSum));


 
/*
run:
 
[0, 1, 3, 6, 10, 15, 21]
 
*/

 

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Answer 4

function accumulate(arr) {
    let sum = 0;
    for (let i = 0; i < arr.length; i++) {
        sum += i;
        console.log(sum + " ");
    }
    console.log("\n");
}
 
 
// 0 : 0+1=1 : 0+1+2=3 : 0+1+2+3=6 : 0+1+2+3+4=10 : 0+1+2+3+4+5=15 ...
arr = [0, 1, 2, 3, 4, 5, 6];
 
accumulate(arr);
 
 
 
/*
run:
 
0 
1 
3 
6 
10 
15 
21 
 
*/

 

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