60pts求调

#include<bits/stdc++.h>
using namespace std;
int csk[1000],sum=0,fp=0,cp=0,i;
char fsk[1000];
string s;
int yxj(char p){
    switch(p){
        case '+':
        case '-':
            return 1;
        case '*':
        case '/':
            return 2;
        case '^':
            return 3;
        default:
        return 0;   
    }
}//if(s[i]=='@') break;
int js(int x,int y,char c){
    if(c=='+') return x+y;
    if(c=='-') return x-y;
    if(c=='*') return x*y;
    if(c=='/') return x/y;
    if(c=='^') return int(pow(x,y));
}
int main()
{
    //string S="test";
    cin>>s;
    //for(int i=0;i<S.size()-1;i++)
     //  s[i]=S[i];
    stack <char> a; 
    for(int j=0;j<s.length();j++)
    {
        if(s[j]=='@') break;
        if(s[j]=='(') a.push(s[i]);
        else if(s[j]==')') 
        {
            if(a.empty()){
                cout<<"NO";
                return 0;
            }
            else a.pop();
        }
    }
    if(!a.empty()) {cout<<"NO"; return 0;}//括号匹配
    for(int i=0;i<s.size()-1;i++)
        if(s[i]=='/'&&s[i+1]=='0') {cout<<"NO"; return 0;}//除0
    for(int i=0;i<s.size();i++)
        if(s[i]=='+'||s[i]=='-'||s[i]=='*'||s[i]=='/')
        	if(s[i+1]=='+'||s[i+1]=='-'||s[i+1]=='*'||s[i+1]=='/')
           		{cout<<"NO"; return 0;}//符号检查 
    s='('+s+')';
	for(int i=1;i<=s.size();i++){
		if(s[i-1]=='('&&s[i]=='-'){
			s.insert(i,"0");
		}
	}

    for(i = 0;i <s.size();i++){
        if(s[i]=='@') break;
        switch(s[i]){
            case '(':
                fsk[++fp] = s[i];
                break;
            case '+':
            case '-':
            case '*':
            case '/':
            case '^':
                while(yxj(s[i])<=yxj(fsk[fp])){
                    int x= csk[cp-1],y = csk[cp];
                    char c = fsk[fp--];
                    csk[--cp] = js(x,y,c);
                }
                fsk[++fp]=s[i];
                break;
            case ')':
                while(fsk[fp]!='('){
                    int x= csk[cp-1],y = csk[cp];
                    char c = fsk[fp--];
                    csk[--cp] = js(x,y,c);
                }
                fp--;
                break;
            default:
                int sum = s[i]-'0';
                for(i++;s[i]>='0'&&s[i] <= '9';i++){
                    sum *=10;
                    sum+=s[i]-'0';
                }
                i--;
                csk[++cp]=sum;
        }
    }
    while(fp>0){
        int x=csk[cp-1],y = csk[cp];
        char c=fsk[fp--];
        csk[--cp]=js(x,y,c);
    }
    printf("%d",csk[cp]);
}