利用QT制作简易计算器

#include "widget.h" #include "ui_widget.h" Widget::Widget(QWidget *parent) : QWidget(parent) , ui(new Ui::Widget) { ui->setupUi(this); //this->setMaximumSize(261,51); //this->setMinimumSize(261,51); this->setWindowTitle("计算器"); } Widget::~Widget() { delete ui; } void Widget::on_oneButton_clicked() { expression += "1"; ui->mainLineEdit->setText(expression); } void Widget::on_zeroButton_clicked() { expression += "0"; ui->mainLineEdit->setText(expression); } void Widget::on_twoButton_clicked() { expression += "2"; ui->mainLineEdit->setText(expression); } void Widget::on_threeButton_clicked() { expression += "3"; ui->mainLineEdit->setText(expression); } void Widget::on_fourButton_clicked() { expression += "4"; ui->mainLineEdit->setText(expression); } void Widget::on_fiveButton_clicked() { expression += "5"; ui->mainLineEdit->setText(expression); } void Widget::on_sixButton_clicked() { expression += "6"; ui->mainLineEdit->setText(expression); } void Widget::on_sevenButton_clicked() { expression += "7"; ui->mainLineEdit->setText(expression); } void Widget::on_eightButoon_clicked() { expression += "8"; ui->mainLineEdit->setText(expression); } void Widget::on_nineButton_clicked() { expression += "9"; ui->mainLineEdit->setText(expression); } void Widget::on_addButton_clicked() { expression += "+"; ui->mainLineEdit->setText(expression); } void Widget::on_subButton_clicked() { expression += "-"; ui->mainLineEdit->setText(expression); } void Widget::on_mulButton_clicked() { expression += "*"; ui->mainLineEdit->setText(expression); } void Widget::on_divButton_clicked() { expression += "/"; ui->mainLineEdit->setText(expression); } void Widget::on_leftButton_clicked() { expression += "("; ui->mainLineEdit->setText(expression); } void Widget::on_rightButton_clicked() { expression += ")"; ui->mainLineEdit->setText(expression); } void Widget::on_clearButton_clicked() { expression.clear(); ui->mainLineEdit->clear(); } void Widget::on_delButton_clicked() { expression.chop(1); ui->mainLineEdit->setText(expression); } void Widget::on_equalButton_clicked() { QStack s_num,s_opt; char opt[128] = {0}; int i = 0 , tmp = 0 , num1 , num2; QByteArray ba; ba = expression.toUtf8(); strcpy(opt,ba.data()); while (opt[i] != '\0' || s_opt.empty() != true) { if(opt[i] >= '0' && opt[i] <= '9') { tmp = tmp * 10 +opt[i] - '0'; i++; if(opt[i] < '0' || opt[i] >'9') { s_num.push(tmp); tmp = 0; } } else { if(s_opt.empty() == true || Priority(opt[i])>Priority (s_opt.top()) ||(s_opt.top()=='('&& opt[i] != ')')) { s_opt.push(opt[i]); i++; continue; } if(s_opt.top() == '(' && opt[i] == ')') { s_opt.pop(); i++; continue; } if(Priority(opt[i]) <= Priority (s_opt.top()) ||(opt[i] == ')' && s_opt.top() != '(' ) ||(opt[i] == '\0' && s_opt.empty() != true)) { char ch = s_opt.top(); s_opt.pop(); switch(ch) { case '+': num1 = s_num.top(); s_num.pop(); num2 = s_num.top(); s_num.pop(); s_num.push(num1 + num2); break; case '-': num1 = s_num.top(); s_num.pop(); num2 = s_num.top(); s_num.pop(); s_num.push(num2 - num1); break; case '*': num1 = s_num.top(); s_num.pop(); num2 = s_num.top(); s_num.pop(); s_num.push(num1 * num2); break; case '/': num1 = s_num.top(); s_num.pop(); num2 = s_num.top(); s_num.pop(); s_num.push(num2 / num1); break; } } } } ui->mainLineEdit->setText(QString::number(s_num.top())); expression.clear(); } int Widget::Priority(char ch) { switch(ch) { case '(': return 3; case '*': case '/': return 2; case '+': case '-': return 1; default: return 0; } }