c/c++语言开发共享char *和char 之间的区别

最直截了当的答案是：

这里的区别在于

 char *s = "Hello world"; 

将Hello世界放在内存的只读部分并制作sa指针，使得对此内存的任何写入操作都是非法的。 做的时候：

 char s[] = "Hello world"; 

将文字字符串放在只读内存中，并将字符串复制到堆栈上新分配的内存中。 从而制作

 s[0] = 'J'; 

法律。

更长的解释将包括存储器存储的段，以及分配的内存量：

 Example: Allocation Type: Read/Write: Storage Location: Memory Used (Bytes): =========================================================================================================== const char* str = "Stack"; Static Read-only Code segment 6 (5 chars plus '') char* str = "Stack"; Static Read-only Code segment 6 (5 chars plus '') char* str = malloc(...); Dynamic Read-write Heap Amount passed to malloc char str[] = "Stack"; Static Read-write Stack 6 (5 chars plus '') char strGlobal[10] = "Global"; Static Read-write Data Segment (R/W) 10 

参考

编辑

为了解决问题中的编辑和随之发布的评论，我在您的解决方案中添加了注释：

 #include  int main() { char ch[] = "Hello"; /* OK; Creating an array of 6 bytes to store * 'H', 'e', 'l', 'l', 'o', '' */ char *p1 = ch; /* OK; Creating a pointer that points to the * "Hello" string. */ char *p2 = p1; /* OK; Creating a second pointer that also * points to the "Hello" string. */ char *p3 = *p1; /* BAD; You are assigning an actual character * (*p1) to a pointer-to-char variable (p3); * It might be more intuitive if written in * 2 lines: * char* p3; * p3 = *p1; //BAD */ printf("ch : %sn", ch); /* OK */ printf("p1 address [%d] value is %sn", p1, *p1); /* Bad format specifiers */ printf("p2 address [%d] value is %sn", p2, *p2); /* Bad format specifiers */ printf("p3 address [%d] value is %sn", p3, *p3); /* Bad format specifiers */ return 0; } 

所以，三个主要的错误。

例子

 #include  int main(void) { char c = 'H'; // A character char* pC = &c; // A pointer to a single character; IS NOT A STRING char cArray[] = { 'H', 'e', 'l', 'l', 'o' }; // An array of characters; IS NOT A STRING char cString[] = { 'H', 'e', 'l', 'l', 'o', '' }; // An array of characters with a trailing NULL charcter; THIS IS A C-STYLE STRING // You could also replace the '' with 0 or NULL, ie: //char cString[] = { 'H', 'e', 'l', 'l', 'o', (char)0 }; //char cString[] = { 'H', 'e', 'l', 'l', 'o', NULL }; const char* myString = "Hello world!"; // A C-style string; the '' is added automatically for you printf("%sn", myString); // OK; Prints a string stored in a variable printf("%sn", "Ducks rock!"); // OK; Prints a string LITERAL; Notice the use of DOUBLE quotes, " " printf("%sn", cString); // OK; Prints a string stored in a variable printf("%cn", c); // OK; Prints a character printf("%cn", *pC); // OK; Prints a character stored in the location that pC points to printf("%cn", 'J'); // OK; Prints a character LITERAL; Notice the use of SINGLE quotes, ' ' /* The following are wrong, and your compiler should be spitting out warnings or even not allowing the * code to compile. They will almost certainly cause a segmentation fault. Uncomment them if you * want to see for yourself by removing the "#if 0" and "#endif" statements. */ #if 0 printf("%sn", c); // WRONG; Is attempting to print a character as a string, similar // to what you are doing. printf("%sn", *pC); // WRONG; Is attempting to print a character as a string. This is // EXACTLY what you are doing. printf("%sn", cArray); // WRONG; cArray is a character ARRAY, not a C-style string, which is just // a character array with the '' character at the end; printf // will continue printing whatever follows the end of the string (ie: // random memory, junk, etc) until it encounters a zero stored in memory. #endif return 0; } 

代码清单 – 提议的解决方案

 #include  int main() { char ch[] = "Hello"; /* OK; Creating an array of 6 bytes to store * 'H', 'e', 'l', 'l', 'o', '' */ char *p1 = ch; /* OK; Creating a pointer that points to the * "Hello" string. */ char *p2 = p1; /* OK; Creating a second pointer that also * points to the "Hello" string. */ char *p3 = p1; /* OK; Assigning a pointer-to-char to a * pointer-to-char variables. */ printf("ch : %sn", ch); /* OK */ printf("p1 address [%p] value is %sn", p1, p1); /* Fixed format specifiers */ printf("p2 address [%p] value is %sn", p2, p2); /* Fixed format specifiers */ printf("p3 address [%p] value is %sn", p3, p3); /* Fixed format specifiers */ return 0; } 

样本输出

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 ch : Hello p1 address [0x7fff58e45666] value is Hello p2 address [0x7fff58e45666] value is Hello p3 address [0x7fff58e45666] value is Hello