C比较指针(带字符) [英] C comparing pointers (with chars)

问题描述

晚上好，我有 2 个函数，每个函数都接受一个指向 char 的指针作为参数:

Good evening, I have 2 functions and each of them accepts as argument a pointer to char:

char pointer[255];
func1(char* pointer)
{
...
memcpy(pointer,some_char,strlen(something));
return;
}
func2(char* pointer)
{
...
if (pointer==someother_char) exit(0); //FAILs
//also I have
if(pointer==someother_pointer2char); // FAILs
}

现在我尝试了 strstr,strcmp 等...不起作用.想尝试 memcmp 但我没有静态 len.因为我必须将 char* 与 char 和 char* 与 char* 进行比较，所以我需要两种解决方案，对吗?

Now I've tried strstr,strcmp etc... doesn't work. Wanted to try memcmp but I don't have static len. As I have to compare char* to char and char* to char* I would be needing two solutions right?

那么，如何以最短的方式比较这些指针(实际上是指针)?

谢谢.

编辑

感谢 wallacer 和 Code Monkey 现在进行 char* 到 char 的比较，我使用以下方法:

func1(char* ptr){
char someother_char[255];
char *ptr_char = NULL; //I have to strcmp a few values so this is why I initialize it first
... 
ptr_char = someother_char;
if (strcmp(ptr,ptr_char) == 0) //gtfo and it does...
...
ptr_char = some2nd;
if(strcmp...

可能有任何建议...(用于比较的外部函数?)

Any suggestions maybe... (hmm external function for comparing?)

建议 1(来自 Code Monkey)

#include <stdio.h>

int main(void) {
    char tempchar[255];
    tempchar[0] = 'a';
    tempchar[1] = 'b';
    tempchar[2] = '';
    char *ptr_char;
    ptr_char = &tempchar[0];
    printf("%s", ptr_char);
    return 0;
}

推荐答案

你需要使用strcmp.没有看到您尝试使用它的方式，这就是您应该使用它的方式:

You need to use strcmp. Not seeing how you tried to use it, this is how you should use it:

char *someother_char = "a";
char *pointer = "a";

if (strcmp(pointer, someother_char) == 0) { // match!
}
else { // not matched 
}

要与 char 进行比较，您必须提升为 char*:

to then do the comparison with a char, you have to promote to a char*:

char *someother_char1;
char test = 'a';
char *pointer = "a";

strncpy((char*)test,someother_char1,sizeof(test));

if (strcmp(pointer, someother_char1) == 0) { // match!
}
else { // not matched 
}

如果你想使用 char array 那么你必须取消引用:

if you want to use the char array then you have to de-reference:

char char_array[255];
// don't forget to fill your array
// and add a null-terminating char somewhere, such as char_array[255] = '';
char *ptr_somechar = &char_array[0];
char *pointer = "a";

if (strcmp(pointer, ptr_somechar) == 0) { // match!
} else { // not matched
}

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