How to solve C++ runtime error: 'invalid type conversion'?

How to solve C runtime error: 'invalid type conversion'?

In the process of C programming, we often encounter various compile-time and run-time errors. One of the common runtime errors is the 'invalid type conversion' error. This error is triggered when we convert one data type to another incompatible data type. This article will cover some common causes of this error and how to resolve it.

The causes of 'invalid type conversion' errors usually include the following:

1. Data type mismatch: When we try to assign different types of data to a variable, the compiler The server may report this error. For example, we are trying to assign a string to an integer variable. In this case we need to convert the string to an integer correctly.

Here is a sample code:

#include <iostream>
using namespace std;

int main() {
    string str = "123";
    int num = str; // 错误：无效的类型转换
    return 0;
}

The way to solve this problem is to use the correct type conversion operator. In this example, we can use the std::stoi function to convert a string to an integer:

int num = stoi(str);

2. Pointer type mismatch: When we try to convert a pointer to This error also occurs when the pointer type is compatible. For example, we are trying to convert a pointer of type int* to a pointer of type char*.

Here is a sample code:

#include <iostream>
using namespace std;

int main() {
    int num = 10;
    char* ptr = (char*)&num; // 错误：无效的类型转换
    return 0;
}

The way to solve this problem is to ensure that the pointer types match. In this example, we can use the reinterpret_cast operator to perform pointer type conversion:

char* ptr = reinterpret_cast<char*>(&num);

3. Type information is lost: Sometimes, we may change between different data types Conversion occurs, but type information is lost due to data range mismatch. In this case, the compiler may report an 'invalid type conversion' error.

Here is a sample code:

#include <iostream>
using namespace std;

int main() {
    int num1 = 1000;
    char num2 = num1; // 错误：无效的类型转换
    return 0;
}

The way to solve this problem is to use the correct data type to save the converted value. In this example, we can use the int type to hold the converted value:

int num2 = num1;

These are some common causes and solutions that can cause 'invalid type conversion' errors. When resolving such errors, we need to carefully check the code and ensure data type compatibility and correct type conversion operations.

To summarize, to solve the C runtime error: 'invalid type conversion', we need to:

1. Check and fix data type mismatches and use appropriate type conversion operations symbol to perform type conversion.
2. Ensure that the pointer types match, use the reinterpret_cast operator to perform pointer type conversion.
3. To avoid the loss of type information caused by data type conversion, choose an appropriate data type to save the converted value.

By understanding and following these methods, we can better solve 'invalid type conversion' errors and improve our C programming skills.

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