int pointer & char pointer

#include <iostream>

using namespace std;

void main()
{
    //int *iPtr = NULL;
    //iPtr = 5; //编译错误：error C2440: “=”: 无法从“int”转换为“int *”
    ////*iPtr = 5; // xxx.exe 中的 0x004113e8 处未处理的异常: 
    ////0xC0000005: 写入位置 0x00000000 时发生访问冲突
    //cout << iPtr << endl;

    //int *iPtr2;
    //*iPtr2 = 3; // Run-Time Check Failure #3 
    ////- The variable 'iPtr2' is being used without being initialized.

    char *cPtr = NULL;
    cPtr = "a";
    printf("%x\n", cPtr);
    cout << cPtr << endl;

    char *cPtr2;
    cPtr2 = "b";
    printf("%x\n", cPtr2);
    cout << cPtr2 << endl;

    /*
    417808
    a
    417800
    b
    请按任意键继续. . .
    */

}