# Construct an identity matrix of order n in JavaScript

JavascriptWeb DevelopmentFront End TechnologyObject Oriented Programming

## Identity Matrix

An identity Matrix is a matrix which is n × n square matrix where the diagonal consist of ones and the other elements are all zeros.

For example an identity matrix of order is will be −

const arr = [
[1, 0, 0],
[0, 1, 0],
[0, 0, 1]
];

We are required to write a JavaScript function that takes in a number, say n, and returns an identity matrix of n*n order.

## Example

Following is the code −

const num = 5;
const constructIdentity = (num = 1) => {
const res = [];
for(let i = 0; i < num; i++){
if(!res[i]){
res[i] = [];
};
for(let j = 0; j < num; j++){
if(i === j){
res[i][j] = 1;
}else{
res[i][j] = 0;
};
};
};
return res;
};
console.log(constructIdentity(num));

## Output

Following is the output on console −

[
[ 1, 0, 0, 0, 0 ],
[ 0, 1, 0, 0, 0 ],
[ 0, 0, 1, 0, 0 ],
[ 0, 0, 0, 1, 0 ],
[
0,
0,
0,
0,
1
]
]
Published on 11-Dec-2020 14:17:26
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