error: narrowing conversion of ‘170’ from ‘int’ to ‘char’ inside

这个错误是由于将一个整数类型的值强制转换为 char 类型时，超出了 char 类型的取值范围所导致的。在 ASCII 码表中，char 类型的取值范围是 0~127，因此当你尝试将一个大于 127 的整数强制转换为 char 类型时，就会出现 narrowing conversion 的错误。要解决这个问题，可以将整数类型改为与 char 类型相同的类型。或者，如果你确定要将这个整数值转换为 char 类型，可以使用 static_cast 进行强制转换，并在转换前确保它不超出 char 类型的取值范围。

相关问题

Clang-Tidy: Narrowing conversion from 'double' to 'int'

This warning message from Clang-Tidy indicates that there is a potential narrowing conversion from a double type to an int type. A narrowing conversion means that some information might be lost during the conversion.

In C++, a double is a floating-point type that can represent decimal numbers with a higher precision compared to an int, which is an integer type. When you assign a double value to an int variable, the compiler may issue a warning because the fractional part of the double value will be truncated, losing precision.

To resolve this warning, you have a few options:

1. If you are intentionally truncating the fractional part, you can use a static_cast to explicitly convert the double value to an int:

   double myDouble = 3.14;
   int myInt = static_cast<int>(myDouble);

2. If you want to perform a rounding operation, you can use the round or nearbyint functions from the `<cmath>` library:

   #include <cmath>

   double myDouble = 3.14;
   int myInt = std::round(myDouble); // or std::nearbyint(myDouble)

3. If you want to avoid the narrowing conversion altogether, you can choose a different type that can represent decimal numbers with higher precision, such as float or double.

It's important to note that the appropriate solution depends on your specific use case and the desired behavior of your program.

Clang-Tidy: Narrowing conversion from 'double' to 'float

'This warning message indicates that there is a possibility of losing precision when converting a double value to a float value. As float has a smaller range and precision as compared to double, the conversion may result in loss of information.

To resolve this warning message, you can consider the following options:

1. Use a float variable instead of a double variable if precision is not a major concern.

2. Use a static_cast operator to explicitly convert the double value to float. This will avoid the warning message and also ensure that the conversion is performed explicitly.

3. Use a double variable instead of a float variable if precision is important.

4. If you are sure that the conversion will not result in loss of information, you can suppress the warning message using the -Wno-float-conversion flag in the compiler options. However, this is not recommended as it can result in unexpected behavior.