用栈实现回文数的判断，参考代码如下:include<stdio.h> int main(){ char str[400]="1212121";char stk[200];int sp=0,l=0,mid,i=0;while(str[l]!=0)++l;mid=l/2;while(i<mid){ stk[sp++]=str[i];++i;} if(l%2!=0)++i;while(i<l)if(stk[--sp]==str[i])++i;else...