如何用 printf 打印 1 个字节? [英] How to print 1 byte with printf?

问题描述

我知道当使用 %x 和 printf() 时，我们从堆栈中打印 4 个字节(一个 int 十六进制).但我只想打印 1 个字节.有没有办法做到这一点?

I know that when using %x with printf() we are printing 4 bytes (an int in hexadecimal) from the stack. But I would like to print only 1 byte. Is there a way to do this ?

推荐答案

假设:你想打印一个1字节宽度的变量的值，即char.

如果您有一个 char 变量，例如 char x = 0; 并且想要打印该值，请使用 %hhx 格式说明符使用 printf().

In case you have a char variable say, char x = 0; and want to print the value, use %hhx format specifier with printf().

类似的东西

 printf("%hhx", x);

否则，由于默认参数提升，像这样的语句

Otherwise, due to default argument promotion, a statement like

  printf("%x", x);

也是正确的，因为printf()不会从stack中读取sizeof(unsigned int)，的值>x 将根据它的类型被读取，无论如何它都会被提升为所需的类型.

would also be correct, as printf() will not read the sizeof(unsigned int) from stack, the value of x will be read based on it's type and the it will be promoted to the required type, anyway.

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