下面这份代码用C++98和C++20输出的结果不一样

#include<iostream>
#include<cstring>
using namespace std;
int main() {
	ios::sync_with_stdio(0);
	string aStr,bStr;
	cin>>aStr>>bStr;
	int aLength=aStr.size(),bLength=bStr.size();
	if(aStr[0]=='-') {
		aStr=aStr.substr(1,aLength--);
		if(bStr[0]=='-') bStr=bStr.substr(1,bLength--);
		else cout<<"-";
	}else if(bStr[0]=='-') {
		bStr=bStr.substr(1,bLength--);
		cout<<"-";
	}
	int length=aLength+bLength; 
	int aInt[aLength],bInt[bLength],ans[length];
	memset(aInt,0,sizeof(aInt));
	memset(bInt,0,sizeof(bInt));
	memset(ans,0,sizeof(ans));
	for(int i=0;i<aLength;i++) aInt[i]=aStr[aLength-i-1]-'0';
	for(int i=0;i<bLength;i++) bInt[i]=bStr[bLength-i-1]-'0';
	int x=0;
	for(int i=0;i<aLength;i++)
		for(int j=0;j<bLength||x;j++) {
			ans[i+j]+=aInt[i]*bInt[j]+x;
			x=ans[i+j]/10;
			ans[i+j]%=10;
		}
	while(ans[length]==0&&length>0) length--;
	for(;length>=0;length--) cout<<ans[length];
    return 0;
}