unsigned char a[10]={'at'}为什么不行
时间: 2024-03-06 22:47:20 浏览: 24
因为一个 unsigned char 只能存储一个字节,即 8 位二进制数,而 'at' 包含两个字符,需要两个字节的存储空间。因此,可以使用字符串字面值来初始化一个 unsigned char 数组,例如:
```
unsigned char a[3] = "at";
```
或者使用字符数组来实现:
```
unsigned char a[2] = {'a', 't'};
```
相关问题
CString转unsigned char
您可以使用以下代码将CString转换为unsigned char数组:
```cpp
CString str = "Hello, World!";
int length = str.GetLength();
unsigned char* buffer = new unsigned char[length];
// 将CString转换为unsigned char数组
for (int i = 0; i < length; i++) {
buffer[i] = (unsigned char)str.GetAt(i);
}
// 使用buffer进行操作...
delete[] buffer;
```
在上面的示例代码中,我们首先获取了CString的长度,然后创建了一个相同长度的unsigned char数组。接下来,我们使用循环将CString的每个字符转换为unsigned char类型,并存储到buffer数组中。最后,您可以使用buffer数组进行进一步的操作。记得在不需要使用buffer数组时,要释放内存,以避免内存泄漏。
void DelayUs(unsigned char Time) { unsigned char a; for(a=0;a<Time;a++) { NOP(); } }
This code snippet defines a function named "DelayUs" that takes an unsigned character (8-bit) argument named "Time". The purpose of this function is to introduce a delay in microseconds (hence the "Us" suffix) using a loop that executes "NOP()" (no operation) instructions.
Inside the function, a variable "a" is declared and initialized to zero. Then, a "for" loop is used that will run as many times as the "Time" argument specifies. Inside the loop body, a single NOP() instruction is executed. This instruction does nothing but take up one clock cycle of the processor. Therefore, as the loop iterates, it introduces a delay that is proportional to the value of "Time".
It is worth noting that this implementation of delay is not very precise or accurate, as it depends on the processor clock speed and other factors that could affect the execution time of the NOP() instruction. Additionally, this function assumes that the microcontroller is running at a clock frequency of at least 1 MHz, as a single NOP() instruction takes one clock cycle to execute.