98 lines
2.6 KiB
JavaScript
98 lines
2.6 KiB
JavaScript
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class Calculator {
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constructor() {
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this.curr = '';
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this.prew = '';
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this.operator = '';
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}
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clear() {
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this.curr = '';
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this.prew = '';
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this.operator = '';
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}
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delete() {
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this.curr = this.curr.slice(0, -1)
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}
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append(val) {
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if (val === '0' && this.curr === '0') {
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this.curr = this.curr;
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} else {
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this.curr = this.curr + val;
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}
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}
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_calculate(prew, curr, operator) {
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switch (operator) {
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case 'ADD':
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return +prew + +curr;
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case 'SUB':
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return +prew - +curr;
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case 'MUL':
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return +prew * +curr;
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case 'DIV':
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return +prew / +curr;
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default:
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console.log('Invalid operator');
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break;
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}
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}
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pressbutton(button) {
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switch (button) {
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case 'ACC':
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this.clear();
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break;
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case 'DEL':
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this.delete();
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break;
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case 'ADD':
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case 'SUB':
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case 'MUL':
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case 'DIV':
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if (this.curr === '' && this.prew !== '') {
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this.operator = button;
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break;
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}
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if (this.curr !== '' && this.prew !== '') {
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this.prew = this._calculate(this.prew, this.curr, this.operator);
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this.curr = '';
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this.operator = '';
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} else {
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if (this.curr === '' && this.prew === '') {
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this.curr = '0';
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}
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this.prew = this.curr;
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this.curr = '';
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}
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this.operator = button;
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break;
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case 'EQU':
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if (this.curr !== '' && this.prew !== '') {
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this.curr = this._calculate(this.prew, this.curr, this.operator);
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this.prew = '';
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this.operator = '';
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}
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break;
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case 'DOT':
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if (this.curr.includes('.')) {
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break;
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}
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if (this.curr === '') {
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this.curr = '0';
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}
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this.append('.')
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break;
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case 'NEG':
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if (this.curr === '') {
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this.curr = '-';
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}
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break;
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default:
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this.append(button)
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break;
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}
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}
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}
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