如何在C中将字符串转换为整数? [英] How to convert a string to integer in C?

问题描述

我正在尝试找出在C中是否存在将字符串转换为整数的另一种方法.

I am trying to find out if there is an alternative way of converting string to integer in C.

我会定期在代码中设置以下内容.

I regularly pattern the following in my code.

char s[] = "45";

int num = atoi(s);

那么，有没有更好的方法或另一种方法?

So, is there a better way or another way?

推荐答案

有 strtol ，这是更好的IMO.我也很喜欢 strtonum ，因此请使用它(但请记住它不是便携式的):

There is strtol which is better IMO. Also I have taken a liking in strtonum, so use it if you have it (but remember it's not portable):

long long
     strtonum(const char *nptr, long long minval, long long maxval,
     const char **errstr);

您可能还对 strtoumax 和 strtoimax 是C99中的标准功能.例如，您可以说:

You might also be interested in strtoumax and strtoimax which are standard functions in C99. For example you could say:

uintmax_t num = strtoumax(s, NULL, 10);
if (num == UINTMAX_MAX && errno == ERANGE)
    /* Could not convert. */

无论如何，请远离 atoi :

调用atoi(str)应等效于:

The call atoi(str) shall be equivalent to:

(int) strtol(str, (char **)NULL, 10)

除了错误处理可能有所不同.如果值不能为表示，行为是不确定的.

except that the handling of errors may differ. If the value cannot be represented, the behavior is undefined.

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