用C的指针和整数的比较 [英] Comparison between pointer and integer in C

问题描述

我对自己在C.程序有点愚蠢​​的问题，我的编译器说我：
的警告：指针和整数的比较。我真的不知道为什么。
我只想写在屏幕上的每个字符。

I have a bit stupid question about program in C. My compiler says me: warning: comparison between pointer and integer. I really don't know why. I only want to write each char on the screen.

我的code：

int i = 0;
char str[50] = {'s', 'a', 'm', 'p','l','e'}; //only for test
while (str[i] != NULL) {
    putchar(str[i]);
    i++;
}

你能帮助我吗？我没有在互联网上找到任何有用的答案。

Can you help me please? I didn't find any usefull answer on the internet.

推荐答案

NULL 是一个指针和海峡[I] 是STR阵列的第i个字符。 char是和整数类型，因为你比较他们，你得到警告。

NULL is a pointer and str[i] is the i-th char of the str array. char is and integer type, and as you compare them you get the warning.

我猜你要检查字符串的结尾，那你会为值为0（字符串结尾）的字符检查做的，那就是'\\ 0'。

I guess you want to check for end of string, that would you do with a check for the char with the value 0 (end of string), that is '\0'.

但是：这不会帮助你，你定义它，就像和字符数组，而不是作为一个字符串，你没有定义字符数组中的termininating 0（你只是运气好，这是隐含在那里）

BUT: this wont help you as you define it just as and array of chars and not as a string, and you didnt define the termininating 0 in the char array (you get just lucky that it is implicit there).

PS：接下来的时间，你至少应该给那里的编译器是抱怨的信息

PS: Next time you should give at least the information where the compiler is complaining.

这篇关于用C的指针和整数的比较的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！