C-字符串常量

相同的字符串常量是共享的，而且是不可写的。

#include <iostream>
using namespace std;

char *string1, *string2;

int main() {
    string1 = "abcd"; string2 = "abcd";
    if(string1 == string2) printf("strings are shared!\n");
    else printf("strings are NOT shared!\n");
    //有可能运行时错误
    //string1[0] = '1';
    if(*string1 == '1') printf("string are writable!\n");
    else printf("string are NOT writable!\n");

    return 0;
}

输出：

$ ./a.exe
strings are shared!
string are NOT writable!