今日总结

std::string generateExpression() {
    // 随机生成带括号的加减乘除表达式的函数
    int num1 = generateRandomNumber(1, 20);
    int num2 = generateRandomNumber(1, 20);
    int num3 = generateRandomNumber(1, 20);
    int op1 = generateRandomNumber(1, 4);
    int op2 = generateRandomNumber(1, 4);

    char oper1, oper2;
    switch (op1) {
        case 1:
            oper1 = '+';
            break;
        case 2:
            oper1 = '-';
            break;
        case 3:
            oper1 = '*';
            break;
        case 4:
            oper1 = '/';
            break;
    }

    switch (op2) {
        case 1:
            oper2 = '+';
            break;
        case 2:
            oper2 = '-';
            break;
        case 3:
            oper2 = '*';
            break;
        case 4:
            oper2 = '/';
            break;
    }

    // 在计算式中添加括号
    std::string expression = "(" + std::to_string(num1) + " " + oper1 + " " + std::to_string(num2) + ") " + oper2 + " " + std::to_string(num3);

    return expression;
}

这是随机生成计算式的代码

double evaluateExpression(const std::string& expression) {
    // 计算表达式结果的函数
    int num1, num2, num3;
    char oper1, oper2;
    sscanf(expression.c_str(), "(%d %c %d) %c %d", &num1, &oper1, &num2, &oper2, &num3);

    double result = 0;
    switch (oper1) {
        case '+':
            result = num1 + num2;
            break;
        case '-':
            result = num1 - num2;
            break;
        case '*':
            result = num1 * num2;
            break;
        case '/':
            result = static_cast<double>(num1) / num2;
            break;
    }

    switch (oper2) {
        case '+':
            result += num3;
            break;
        case '-':
            result -= num3;
            break;
        case '*':
            result *= num3;
            break;
        case '/':
            result /= num3;
            break;
    }

    return result;
}