带有分段错误(核心转储)错误的 C 中的指针 [英] Pointers in C with Segmentation fault (core dumped) error

问题描述

我只是想测试我是否正确安装了新的 ide 并尝试在 IDE 中以及使用 gedit 和 GCC 编译这个基本程序，它可以编译，但在我在命令行中启动可执行文件后崩溃 -我不知道出了什么问题，因为我对 C 中的指针还很陌生，根据大多数人的说法，需要一段时间来理解这个理论.

I was just trying to test if I installed a new ide correctly and tried to compile this basic program, both in the IDE and with gedit and GCC and it would compile, but crash after I launch the executable in the command line - I have no idea what's wrong, as I'm still fairly new to pointers in C and it takes a while to wrap your head around the theory, according to most people.

代码:

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

    char print_func(char *hi);

    int main(void) {
        char *hi = "Hello, World!";
        print_func(*hi);
    }

    char print_func(char *hi) {
        printf("%d \n", *hi);
    }

我试过了:

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

char print_func(char *hi);

int main(void) {
    char *hi = "Hello, World!";
    print_func(&hi);
}

char print_func(char *hi) {
    printf("%d \n", *hi);
}

它输出 44，没有崩溃.

and it outputs 44 with no crash.

推荐答案

如果您使用 print_func(*hi); 进行间接寻址，则您传递的是一个字符，它是一个字节.因此，当您尝试读取一个更大的整数时，就会发生访问冲突.您应该使用指针print_func(hi) 调用您的函数.而如果要打印字符串的地址，最好在printf中使用%p:

If you do indirection using, print_func(*hi); you are passing a char and it is one byte. So when you are trying to read an integer, which is larger, an access violation occurs. You should call your function with a pointer print_func(hi). And if you want to print the address of a string, it is better to use %p in printf:

printf("%p \n", hi); // print the address of hi

如果要打印 hi 中的第一个字符，请改用 %c:

If you want to print the first character in use %c instead:

printf("%c \n", *hi); // print first character of hi

如果要打印 hi 中第一个字符的值，请改用 %d，并进行强制转换:

If you want to print the value of the first character in use %d instead, with casting:

printf("%d \n", (int)*hi); // print the value of the first character of hi

要打印整个字符串，请使用 %s 并传递指针:

To print the whole string use %s and pass the pointer:

printf("%s \n", hi);

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