每次运行此代码时，我都会得到3.但它应该是10.如何修复它？ [英] Every time I run this code, I get 3. But it should be 10. How to fix it?

问题描述

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main()
{
    int n;
    char* element[] = "Hydrogen" ,"Helium", "Lithium", "Beryllium", "Boron", "Carbon", "Nitrogen", "Oxygen", "Fluorine", "Neon" };
    n=strlen(element);
    printf("%d",n);
    return 0;
}

我的尝试：

What I have tried:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main()
{
    int n;
    char* element[] = {"Hydrogen","Helium","Lithium","Beryllium","Boron","Carbon","Nitrogen","Oxygen","Fluorine","Neon"};
    n=strlen(element);
    printf("%d",n);
    return 0;
}

推荐答案

如果你看一下strlen的定义： strlen - C ++参考 [ ^ ]它接受一个参数，它是一个指向char的指针 - 换句话说就是一个字符串 - 并返回第一个空值的字符数。

这不是传递它的内容： element 是一个指向char的指针数组 - 或一个字符串数组。因此，它将数组看作是一个字符串，并且让它非常错误。



将它传递给数组的一个元素，它将返回你想要什么！

If you look at the definition of strlen: strlen - C++ Reference[^] it takes a parameter which is a pointer to a char - or a string in other words - and returns the number of characters up to the first null value.
That isn't what to are passing it: element is an array of pointers to char -or an array of strings. So it looks at the array as if it was a string, and gets it horribly wrong.

Pass it one of the elements of the array, and it'll return what you want!

n=strlen(element[0]);

或

n=strlen(element[1]);

...

在编译时已知数组的大小。通常使用如下的宏

The size of an array is known at compile time. Usually a macro like the following is used

#define NELEM(a)  (sizeof(a) / sizeof(a[0]))

尝试，例如

Try, for instance

#include <stdio.h>

#define NELEM(a)  (sizeof(a) / sizeof(a[0]))

int main()
{
    int n;
    char* element[] = { "Hydrogen" ,"Helium", "Lithium", "Beryllium", "Boron", "Carbon", "Nitrogen", "Oxygen", "Fluorine", "Neon" };
    n = NELEM(element);
    printf("%d\n",n);
    return 0;
}

我们不能使用strlen来获取数组中元素的数量。



我已经为你解决了，并链接如下。



数组的长度字符串 [ ^ ]

We can not use strlen to get the count of elements in an array.

I have solved for you and linked as below.

length of an array of strings[^]

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