#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
int main()
{
	int a[256],b[256],c[256],lena,lenb,lenc,i;
	char n[256],n1[256],n2[256];
	memset(a,0,sizeof(a));
	memset(b,0,sizeof(b));
	memset(c,0,sizeof(c));
	cin>>n1;
	cin>>n2;
	if(strlen(n1)<strlen(n2) || (strlen(n1)==strlen(n2) && strcmp(n1,n2)<0))
	{
		strcpy(n,n1);
		strcpy(n1,n2);
		strcpy(n2,n);
		cout<<"-";
	}
	lena=strlen(n1);lenb=strlen(n2);
	for(i=0;i<=lena-1;i++) a[lena-i]=int(n1[i]-'0');
	for(i=0;i<=lenb-1;i++) b[lenb-i]=int(n2[i]-'0');
	i=1;
	while(i<=lena||i<=lenb)
	{
		if(a[i]<b[i])
		{
		a[i]+=10;
		a[i+1]--;
	}
	c[i]=a[i]-b[i];
	i++;
	}
	lenc=i;
	while((c[lenc]==0) && (lenc>1)) lenc--;
	for(i=lenc;i>=1;i--) cout<<c[i];
	cout<<endl;
}

在编辑时点那个大括号里面有个斜杠的标识，然后把代码拖进去有奇效

zan