不得不说这道题坑！！！！ 格式化输出 真的很D区 不格式化就错 wuwuwuwuwuuwu

import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int i = 1;
        while (n > 0) {
            // 注意用next 不可以用nextLine() 才能输入两个数值
            String a = sc.next();
            String b = sc.next();
            // 因为数不超过1000位，用一个数组存放大数
            int c[] = new int[1001];
            // 输入a 得到的长度
            int lengthA = a.length();
            // 输入b 得到的长度
            int lengthB = b.length();
            // 得到数组的长度
            int lengthC = c.length;
            // 一开始进位为0
            int temp = 0;
            int flag = Math.min(lengthA, lengthB);
            while (flag > 0) {
//看看两个数的末尾
                int i1 = a.charAt(lengthA - 1) - '0';
                int i2 = b.charAt(lengthB - 1) - '0';
                c[lengthC - 1] = (i1 + i2 + temp) % 10;
                temp = (i1 + i2 + temp) / 10;
                lengthA--;
                lengthB--;
                lengthC--;
                flag--;
            }
//看那个数还没完全处理完 继续处理
            flag = (lengthA > lengthB) ? lengthA : lengthB;
            String tx = (lengthA > lengthB) ? a : b;
            if (flag > 0) {
                while (flag > 0) {
                    c[lengthC - 1] = (temp + tx.charAt(flag - 1) - '0') % 10;
                    temp = (temp + tx.charAt(flag - 1) - '0') / 10;
                    flag--;
                    lengthC--;
                }
            }
//逐个加到字符串里面
            c[lengthC - 1] = temp;
            StringBuffer str = new StringBuffer("");
            boolean x = false;
            for (int i2 = 0; i2 < c.length; i2++) {
                if (c[i2] != 0) {
                    x = true;
                }
                if (x == true) {
                    str = str.append(c[i2]);
                }
            }
            System.out.println("Case " + i + ":");
            System.out.print(a + " + " + b + " = " + str);
//          敲重点 在这里有问题 格式
            if(n != 1){
                 System.out.println();
             }
             System.out.println();
            n--;
            i++;
        }
    }
}

#include "pch.h"
#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <string>
#include <map>
#include <stack>
#include <vector>
#include <set>
#include <queue>
#include <iomanip>
#define maxn 15
#define MAXN 100005
#define mod 1000000007
#define INF 0x3f3f3f3f
#define exp 1e-6
#define pi acos(-1.0)
using namespace std;
int main()
{
    //freopen("D:\\a.txt","r",stdin);
    ios::sync_with_stdio(false);
    char a1[1000], b1[1000];
    int  a[1000], b[1000], c[1000], lena, lenb, lenc, i, x;
    int t, cas = 0;
    cin >> t;
    while (t--)
    {
        cas++;
        memset(a, 0, sizeof(a));
        memset(b, 0, sizeof(b));
        memset(c, 0, sizeof(c));
        cin >> a1 >> b1;
        lena = strlen(a1);
        lenb = strlen(b1);
        for (i = 0; i <= lena - 1; i++)
            a[lena - i] = a1[i] - 48;
        for (i = 0; i <= lenb - 1; i++)
            b[lenb - i] = b1[i] - 48;
        lenc = 1;
        x = 0;
        while (lenc <= lena || lenc <= lenb)
        {
            c[lenc] = a[lenc] + b[lenc] + x;
            x = c[lenc] / 10;
            c[lenc] %= 10;
            lenc++;
        }
        c[lenc] = x;
        if (c[lenc] == 0)
            lenc--;
        cout << "Case " << cas << ":" << endl;
        for (i = 0; i <= lena - 1; i++)
            cout << a1[i];
        cout << " + ";
        for (i = 0; i <= lenb - 1; i++)
            cout << b1[i];
        cout << " = ";
        for (i = lenc; i >= 1; i--)
            cout << c[i];
        cout << endl;
        if (t)
            cout << endl;
    }
    return  0;
}