c++ - 未在此范围错误中声明

Question

我想让这个程序计算工资总额，但它输出错误。

#include<stdio.h>

int main() {
    float base-salary = 1500.00;
    float bonus-rate = 200.00;
    float commission-rate = quantity * 2/100;
    int quantity;
    float Price;
    float Gross-salary;

    printf("Enter quantity of computers sold\n");
    scanf("%d",&quantity);
    printf("Enter Price of computers sold\n");
    scanf("%f",&Price);

    Gross-salary = base-salary + (quantity * bonus-rate) + (quantity * Price) * commission-rate;
    printf("Gross salary equals :%f",Gross-salary);


    //Gross salary = base salary + (quantity * bonus rate) + (quantity * Price) * commission rate


}

它吐出这些错误。

5 13 Documents\Untitled10.cpp [Error] expected initializer before '-' token 16 2 Documents\Untitled10.cpp [Error] 'Gross' was not declared in this scope 16 2 Documents\Untitled10.cpp [Error] 'base' was not declared in this scope 16 2 Documents\Untitled10.cpp [Error] 'salary' was not declared in this scope 16 2 Documents\Untitled10.cpp [Error] 'bonus' was not declared in this scope 16 2 Documents\Untitled10.cpp [Error] 'rate' was not declared in this scope 16 2 Documents\Untitled10.cpp [Error] 'commission' was not declared in this scope

Answer 1

您不能在 C++ 标识符名称中使用 - 破折号。切换为下划线。

引用http://en.cppreference.com/w/cpp/language/identifiers :

An identifier is an arbitrarily long sequence of digits, underscores, lowercase and uppercase Latin letters, and most Unicode characters (disallowed are control characters and characters in the basic source character set). A valid identifier must begin with a non-digit character (Latin letter, underscore, or Unicode non-digit character). Identifiers are case-sensitive (lowercase and uppercase letters are distinct), and every character is significant.

此外，在计算中使用浮点除法，而不是整数。

float commission-rate = quantity * 2/100;

由于数量是int，所以会进行整数除法，你只会得到结果的截断部分。这样做:

float commission_rate = quantity * 2/100.f;

在声明变量之前使用变量还有另一个错误:

float commission_rate = quantity * 2/100;
int quantity;

数量未声明，因此不能在第 1 行中使用。交换这些语句。另外，请注意 C++ 不是一种符号数学语言。在评估表达式时获取变量值。这是一个常见的初学者错误，首先声明一个公式，然后初始化它包含的变量。因此，第 1 行必须移到输入部分下方。

您的固定代码可能如下所示:

const float base_salary = 1500.f;
const float bonus_rate = 200.f;
int quantity;
float price;
float gross_salary;

printf("Enter quantity of computers sold\n");
scanf("%d",&quantity);
printf("Enter Price of computers sold\n");
scanf("%f",&price);

const float commission_rate = quantity * 2/100.f;
const gross_salary = base_salary + quantity * bonus_rate + \
                     quantity * price * commission_rate;
printf("Gross salary equals :%f",gross_salary);