ds-algo-study/DS-n-Algos/Recursion/My-Recursion-Prac-Website/Recur-website/AUX_MATERIALS/sandbox/sum.js

Just experimenting with publishing a package

//  We want to write a function recursiveSum(array) which takes an array
//    of numbers and returns the sum of all elements of the array.
//  This problem must be solved recursively.


// Repeating pattern
//  Adding elements in the array

// Where does the pattern break
// When we're at the last element

// Base Case
// when arr.length === 1

// Recursive Case
// when arr.length > 1

// Recrusive Step
// recursiveSum(arr.slice(1))


function recursiveSum ( array ) {
    if ( array.length === 1 ) {
        return array[ 0 ];
    }

    return array[ 0 ] + recursiveSum( array.slice( 1 ) );
}

const array = [ 2, 4, 3, 6 ];

recursiveSum( array );


// recursiveSum(array);   // 1st frame,   array = ,   newArray = 
// recursiveSum(array);   // 2nd frame,   array = ,    newArray = 
// recursiveSum(array);   // 3rd frame,   array = ,     newArray = 
// recursiveSum(array);   // 4th frame,   array = ,      returns ,    popped off the stack
// 3rd frame,     sum= ,    returns ,     popped off the stack
// 2nd frame,     sum= ,    returns ,     popped off the stack
// 1st frame,     sum= ,    returns ,     popped off the stack
// Final return value:


console.log( recursiveSum( array ) );