JavaScript 中的数组元素之和

Question

I'm trying to solve this problem where I initialize an array of 5 elements and print the sum of the elements. I can't wrap my head around the logic behind the solution. Please review my code.

Another problem with reading an array of 5 integers and printing the smallest element. I keep getting the wrong answer...

This's a script embedded inside an HTML file.

Problem 1

var num= [1,1,1,1]; 

var total=num[0];
for( var i=0 ; i < num.length ; i++)
    { 

     total =+num[i]; 
    }


window.alert("The total is "+ total); 

I expected the answer to be 4, but all I get is 1.

---

Problem 2

var r = new Array(5);

var len = r.length; 

for(var i=0 ; i <len ; i++)
    {
        r[i] = window.prompt("Enter the elements of the array");
    }


 var small= [0];

for(var j=0; j< len ; j++)
    { 
     if(r[i] < small )
         small = r[i];
    }

window.alert("The smallest element is the array is "+small);

I get the last element in my array as the smallest element which's obviously isn't right.

Answer 1

In problem 1) you just need to change =+ to +=

In problem 2) you need to start in the first element of r and in the for loop you need index the r array by the variable j instead of i variable

var r = new Array(5);
var len = r.length; 

for(var i=0 ; i <len ; i++)
{
    r[i] = window.prompt("Enter the elements of the array");
}

var small = r[0];

for( var j=0; j< len ; j++)
{ 
    if(r[j] < small )
        small = r[j];
}

window.alert("The smallest element is the array is "+small);

But you could just do:

const min = Math.min(...r)
window.alert("The smallest element is the array is "+ min);

Answer 2

There are a couple things here.

For problem 1: Since you initialize the total to the first item I think you end up counting it 2 times. Likely you'd want to initialize to 0. var total = 0 . You will also want to use += instead of =+ the latter sets the value instead of adding it.

For Problem 2: new Array(5) creates a new sparse array. It's kinda weird. It's like it's full of undefined values. So when you assign small you'll want to access the first element of r , var small = r[0] but that will be undefined due to r being a sparse array. So you'll want var r = new Array(5).fill().map((x,i) => i) to set values in that array. You will also want to use j instead of i in the body of the second loop.

That should do it;).

Answer 3

Hi The problem 1 could be tackled with reduce method check the Docs here :

The problem 2 could be solved with Math.min method:

var num= [1,1,1,1]; 
var numMin= [100,1121,1212,122, 12]; 

//Problem1
let totalSum = num.reduce( ( accumulator, currentItem ) => {
 return accumulator = accumulator += currentItem;
} , 0 );

console.log(totalSum)

//Problem 2
console.log( 'Min',Math.min( ...numMin ) );

Here is a replit so you can play with the code

Answer 4

 // Find array elements sum let total = 0; let arr = [1,2,3,4]; arr.map(el => total+=el); console.log(total); // 10

Answer 5

 // Find array smallest element let arr = [1,-2,13,-4,7]; let smlEl = arr[0] arr.map(el => { if(el < smlEl) { smlEl = el; } }) console.log(smlEl); // -4