linux中的gdb C代码 – 地址超出范围

#include <stdio.h>

    char strA[80] = {"string to be used for demonstration purposes."};
    char strB[80];

    int main(void){
      char *pA;      //A pointer to type char
      char *pB;      //Another pointer to type char
      puts(strA);    //Show string A
      pA = strA;     //Point pA to string A
      puts(pA);      //Show what pA is pointing to
      //printf("pA = %s",pA);
      pB = strB;     //Point pB to string B           
      putchar('n'); //Move down one line on the screen

      while(*pA != ''){
        *pB++ = *pA++;
      }

      *pB = '';
      puts(strB);    //Show string B on the screen

      return 0;

    }

现在我使用gdb进行调试,并执行以下步骤：

gdb str
break main
run
x/s $esp

但在这里我得到了“如果有界限的地址”错误……
有谁可以告诉我如何解决它？
谢谢