scanf（“％d”，char *） - char-as-int格式字符串？ [英] scanf("%d", char*) - char-as-int format string?

问题描述

char-as-number的格式字符串修饰符是什么？

我想读入一个永不超过255

使用典型

  ] =x32; 
 char separator; 
 unsigned char dest; 
 int len; 
 
 len = sscanf（source，％c％d，& separator，& dest）; 
 //验证并继续... 
  

我得到预期的警告：参数4的sscanf是类型char *，int *预期。

根据我的理解规范，没有char的修饰符（例如％sd简写或％lld 64位元）

• 是危险的吗？ （将溢出只是溢出（翻转）变量或将它写在所分配的空间之外？）


• 是否有一个更好的方式来实现分配一个临时int变量？

解决方案 div>

您可以在glibc的％hhd ncorfer> scanf（） ，MSVC似乎不支持整数存储到一个char直接（参见MSDN scanf Width Specification 了解有关支持的转换的详情）

What is the format string modifier for char-as-number?

I want to read in a number never exceeding 255 (actually much less) into an unsigned char type variable using sscanf.

Using the typical

 char source[] = "x32";
 char separator;
 unsigned char dest;
 int len;

 len = sscanf(source,"%c%d",&separator,&dest);
 // validate and proceed...

I'm getting the expected warning: argument 4 of sscanf is type char*, int* expected.

As I understand the specs, there is no modifier for char (like %sd for short, or %lld for 64-bit long)

• is it dangerous? (will overflow just overflow (roll-over) the variable or will it write outside the allocated space?)
• is there a prettier way to achieve that than allocating a temporary int variable?
• ...or would you suggest an entirely different approach altogether?

解决方案

You can use %hhd under glibc's scanf(), MSVC does not appear to support integer storage into a char directly (see MSDN scanf Width Specification for more information on the supported conversions)

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