Language: C++


#if 1
#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <map>
#include <set>
#include <unordered_map>
#include <unordered_set>
#include <queue>
#include <stack>
#include <array>
#include <deque>
#include <algorithm>
#include <utility>
#include <cstdint>
#include <functional>
#include <iomanip>
#include <numeric>
#include <assert.h>
#include <bitset>

auto& in = std::cin;
auto& out = std::cout;

char aaa[50];
int32_t a, b, c, d;
#define beet(x,y,z) if(a x b y c z d==7){out<<a<<#x<<b<<#y<<c<<#z<<d<< "=7\n";return 0;}
int main()
{
	using std::endl;
	in.sync_with_stdio(false);
	out.sync_with_stdio(false);
	in.tie(nullptr);
	out.tie(nullptr);

	in >> aaa;
	a = aaa[0] - '0';
	b = aaa[1] - '0';
	c = aaa[2] - '0';
	d = aaa[3] - '0';
	if (a + b + c + d== 7) { out << a << + << b << + << c << + << d << "=7\n"; return 0; }
	if (a + b + c - d== 7) { out << a << + << b << + << c << - << d << "=7\n"; return 0; }
	if (a + b - c + d== 7) { out << a << + << b << - << c << + << d << "=7\n"; return 0; }
	if (a + b - c - d== 7) { out << a << + << b << - << c << - << d << "=7\n"; return 0; }
	if (a - b + c + d== 7) { out << a << - << b << + << c << + << d << "=7\n"; return 0; }
	if (a - b + c - d== 7) { out << a << - << b << + << c << - << d << "=7\n"; return 0; }
	if (a - b - c + d== 7) { out << a << - << b << - << c << + << d << "=7\n"; return 0; }
	if (a - b - c - d== 7) { out << a << - << b << - << c << - << d << "=7\n"; return 0; }

	return 0;
}
#endif

Compiler output:
a.cc: In function 'int main()':
a.cc:43:48: error: expected primary-expression before '<<' token
   43 |         if (a + b + c + d== 7) { out << a << + << b << + << c << + << d << "=7\n"; return 0; }
      |                                                ^~
a.cc:43:58: error: expected primary-expression before '<<' token
   43 |         if (a + b + c + d== 7) { out << a << + << b << + << c << + << d << "=7\n"; return 0; }
      |                                                          ^~
a.cc:43:68: error: expected primary-expression before '<<' token
   43 |         if (a + b + c + d== 7) { out << a << + << b << + << c << + << d << "=7\n"; return 0; }
      |                                                                    ^~
a.cc:44:48: error: expected primary-expression before '<<' token
   44 |         if (a + b + c - d== 7) { out << a << + << b << + << c << - << d << "=7\n"; return 0; }
      |                                                ^~
a.cc:44:58: error: expected primary-expression before '<<' token
   44 |         if (a + b + c - d== 7) { out << a << + << b << + << c << - << d << "=7\n"; return 0; }
      |                                                          ^~
a.cc:44:68: error: expected primary-expression before '<<' token
   44 |         if (a + b + c - d== 7) { out << a << + << b << + << c << - << d << "=7\n"; return 0; }
      |                                                                    ^~
a.cc:45:48: error: expected primary-expression before '<<' token
   45 |         if (a + b - c + d== 7) { out << a << + << b << - << c << + << d << "=7\n"; return 0; }
      |                                                ^~
a.cc:45:58: error: expected primary-expression before '<<' token
   45 |         if (a + b - c + d== 7) { out << a << + << b << - << c << + << d << "=7\n"; return 0; }
      |                                                          ^~
a.cc:45:68: error: expected primary-expression before '<<' token
   45 |         if (a + b - c + d== 7) { out << a << + << b << - << c << + << d << "=7\n"; return 0; }
      |                                                                    ^~
a.cc:46:48: error: expected primary-expression before '<<' token
   46 |         if (a + b - c - d== 7) { out << a << + << b << - << c << - << d << "=7\n"; return 0; }
      |                                                ^~
a.cc:46:58: error: expected primary-expression before '<<' token
   46 |         if (a + b - c - d== 7) { out << a << + << b << - << c << - << d << "=7\n"; return 0; }
      |                                                          ^~
a.cc:46:68: error: expected primary-expression before '<<' token
   46 |         if (a + b - c - d== 7) { out << a << + << b << - << c << - << d << "=7\n"; return 0; }
      |                                                                    ^~
a.cc:47:48: error: expected primary-expression before '<<' token
   47 |         if (a - b + c + d== 7) { out << a << - << b << + << c << + << d << "=7\n"; return 0; }
      |                                                ^~
a.cc:47:58: error: expected primary-expression before '<<' token
   47 |         if (a - b + c + d== 7) { out << a << - << b << + << c << + << d << "=7\n"; return 0; }
      |                                                          ^~
a.cc:47:68: error: expected primary-expression before '<<' token
   47 |         if (a - b + c + d== 7) { out << a << - << b << + << c << + << d << "=7\n"; return 0; }
      |                                                                    ^~
a.cc:48:48: error: expected primary-expression before '<<' token
   48 |         if (a - b + c - d== 7) { out << a << - << b << + << c << - << d << "=7\n"; return 0; }
      |                                                ^~
a.cc:48:58: error: expected primary-expression before '<<' token
   48 |         if (a - b + c - d== 7) { out << a << - << b << + << c << - << d << "=7\n"; return 0; }
      |                                                          ^~
a.cc:48:68: error: expected primary-expression before '<<' token
   48 |         if (a - b + c - d== 7) { out << a << - << b << + << c << - << d << "=7\n"; return 0; }
      |                                                                    ^~
a.cc:49:48: error: expected primary-expression before '<<' token
   49 |         if (a - b - c + d== 7) { out << a << - << b << - << c << + << d << "=7\n"; return 0; }
      |                                                ^~
a.cc:49:58: error: expected primary-expression before '<<' token
   49 |         if (a - b - c + d== 7) { out << a << - << b << - << c << + << d << "=7\n"; return 0; }
      |                                                          ^~
a.cc:49:68: error: expected primary-expression before '<<' token
   49 |         if (a - b - c + d== 7) { out << a << - << b << - << c << + << d << "=7\n"; return 0; }
      |                                                                    ^~
a.cc:50:48: error: expected primary-expression before '<<' token
   50 |         if (a - b - c - d== 7) { out << a << - << b << - << c << - << d << "=7\n"; return 0; }
      |                                                ^~
a.cc:50:58: error: expected primary-expression before '<<' token
   50 |         if (a - b - c - d== 7) { out << a << - << b << - << c << - << d << "=7\n"; return 0; }
      |                                                          ^~
a.cc:50:68: error: expected primary-expression before '<<' token
   50 |         if (a - b - c - d== 7) { out << a << - << b << - << c << - << d << "=7\n"; return 0; }
      |                                                                    ^~