C函数形参里面为何要用:const char *inputString

const char*可以访问inputString所指向的数据，又可以避免修改原来的字符串。
const int x; // constant int
x = 2; // illegal - can't modify x

const int* pX; // changeable pointer to constant int
*pX = 3; // illegal - can't use pX to modify an int
pX = &someOtherIntVar; // legal - pX can point somewhere else

int* const pY; // constant pointer to changeable int
*pY = 4; // legal - can use pY to modify an int
pY = &someOtherIntVar; // illegal - can't make pY point anywhere else

const int* const pZ; // const pointer to const int
*pZ = 5; // illegal - can't use pZ to modify an int
pZ = &someOtherIntVar; // illegal - can't make pZ point anywhere else