How to add up in javascript

Javascript method to implement accumulation: first create the corresponding js sample file; then implement accumulation through "for(var i = 1;i <= 100;i){sum = i;}" and other methods. Can.

The operating environment of this article: windows7 system, javascript version 1.8.5, Dell G3 computer.

How to accumulate in javascript?

JS common algorithm-accumulation/accumulation

Accumulation: Add a series of data to a variable. Finally, the cumulative result is obtained.

empty
var sum = 0;
for(var i = 1;i <= 100;i++){
    sum += i;
}

empty
var h = 100;
var sum = 0;
for(var i = 0;i < 10;i++){
    h = h / 2;
    sum += h;
}
sum = sum * 2 + 100;

Accumulation: Multiply a series of data into a variable to get the cumulative result.

empty
var n = 100;
var result = 1;
for(var i = 1;i <= n;i++){
    result *= i;
}

General form:

Accumulation: v = e;

Accumulation: v *= e;

v represents accumulation Sum/accumulation, e represents the accumulation/accumulation term

Key points of the algorithm:

(1)Initialization

Initialization v:

Accumulation: v = 0;

Accumulation: v = 1;

e initialization, if the accumulation/product term is more complex, it may be decomposed into several sub-terms to be initialized separately. For example, in the problem of calculating pi, the accumulation term is decomposed into The three parts of the symbol, numerator and denominator

(2) The control condition of the loop

One is a fixed number of times, such as the problem of calculating the bounce distance, the problem of calculating the sum of the first 20 items of the sequence, the number of times It is not fixed, but must meet a certain condition: the problem of calculating pi requires that the absolute value of the last term be less than 10-6.

(3) Determine the accumulation/product term

For example, the sum of the first 20 items in a sequence is to use the sum of the current numerator and denominator as the next denominator, and the current denominator as the numerator;

Another example is to find the circumference of pi. The sign is inverted, the denominator is 2, and then the next term is obtained.

[Recommended learning: javascript advanced tutorial]

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