主要靠的是栈内栈外优先级的设置:
#include"iostream" #include"stdio.h" #include"stack" #include"algorithm" #include"string" #include"ctype.h" using namespace std; struct node { char ch; int isp,icp; }; char a[100]; void f(node &d) { switch(d.ch){ case '(':d.isp=1;d.icp=6;break; case '*':case '/':case '%': d.isp=5;d.icp=4;break; case '+':case '-': d.isp=3;d.icp=2;break; case ')':d.isp=6;d.icp=1;break; case '#':d.isp=d.icp=0;break; default:break; } } int main() { node b,t; stack<node>s; node c;c.ch='#'; f(c); s.push(c); cin>>b.ch; while(!s.empty()) { if(isdigit(b.ch)) {cout<<b.ch;cin>>b.ch;} else { f(b); t=s.top(); if(b.icp>t.isp) {s.push(b);cin>>b.ch;} else if(b.icp<t.isp) {cout<<t.ch;s.pop();} else {s.pop();if(t.ch=='(') cin>>b.ch;} } } return 0; }