Language: C++

#include <iostream>
#include <string>
#include <sstream>
#include <iomanip> 
#include <math.h>
#include <stdio.h>
#include <string.h>
#include <queue>
#include <stack>
#include <vector>
#include <map>
#include <set>
#include <functional>
#include <algorithm>
#include <unordered_map>
#include <unordered_set>
#include <bitset>

using namespace std;


#define MAXN 150000			// total # of prime numbers
#define MAXP 1001002		// highest number to test prime

int prime[MAXN];		// prime numbers: 2, 3, 5 ...
int lp[MAXP];		// lp[n] = n if n is prime; otherwise smallest prime factor of the number
int phi[MAXP];			// phii function

class prime_class {
public:
	long top;

	prime_class() {			// generate all prime under MAXP
		int i, i2, j;

		top = 0;
		lp[0] = 0;
		lp[1] = 1;
		for (i = 2; i < MAXP; i++) lp[i] = 0;

		top = 0;
		for (i = 2; i < MAXP; ++i) {
			if (lp[i] == 0) {
				lp[i] = i;
				prime[top++] = i;
			}
			for (j = 0; (j < top) && (prime[j] <= lp[i]) && (i * prime[j] < MAXP); ++j)
				lp[i * prime[j]] = prime[j];
		}
	}

	bool isprime(int key)
	{
		if (key < MAXP)	return (lp[key] == key) && (key >= 2);
		else {
			int i;
			for (i = 0; (i < top) && (prime[i] * prime[i] <= key); i++)
				if (key % prime[i] == 0) return false;
			return true;
		}
	}

	unordered_map<int, int> factorize(int key) {
		unordered_map<int, int> ans;

		while (lp[key] != key) {
			ans[lp[key]]++;
			key /= lp[key];
		}
		if (key > 1) ans[key]++;

		return ans;
	}

	int get_phi(int key) {	// calculate Euler's totient function, also known as phi-function
		int ans = key, last = 0;

		while (lp[key] != key) {
			if (lp[key] != last) {
				last = lp[key];
				ans -= ans / last;
			}
			key /= lp[key];
		}
		if ((key > 1) && (key != last)) ans -= ans / key;

		return ans;
	}

	void calc_all_phi(int n) {
		int i, j, k;
		for (int i = 1; i < n; i++) phi[i] = i;
		for (int i = 2; i < n; i++) {
			if (phi[i] == i) {
				for (int j = i; j < n; j += i) {
					phi[j] /= i;
					phi[j] *= i - 1;
				}
			}
		}
	}

	vector<pair<long long, long long>> factorize_full(long long key) {		// can be used to factorize numbers >= MAXP
		vector<pair<long long, long long>> ans;

		long i, ct;

		for (i = 0; (i < top) && (prime[i] <= key); i++)
			if (key % prime[i] == 0) {
				ct = 0;
				while (key % prime[i] == 0) {
					ct++;
					key /= prime[i];
				}
				ans.push_back({ prime[i], ct });
			}
		if (key > 1) {
			ans.push_back({ key, 1 });
		}
		return ans;
	}

	void generate_divisors(int step, int v, vector<pair<int, int>>& fp, vector<int>& ans) {
		if (step < fp.size()) {
			generate_divisors(step + 1, v, fp, ans);
			for (int i = 1; i <= fp[step].second; i++) {
				v *= fp[step].first;
				generate_divisors(step + 1, v, fp, ans);
			}
		}
		else ans.push_back(v);
	}

	void generate_divisors_full(long long step, long long v, vector<pair<long long, long long>>& fp, vector<long long>& ans) {
		if (step < fp.size()) {
			generate_divisors_full(step + 1, v, fp, ans);
			for (int i = 1; i <= fp[step].second; i++) {
				v *= fp[step].first;
				generate_divisors_full(step + 1, v, fp, ans);
			}
		}
		else ans.push_back(v);
	}

	vector<int> get_divisors(int key) {
		unordered_map<int, int> f = factorize(key);
		int n = f.size();
		vector<pair<int, int>> fp;
		for (auto p : f) fp.push_back(p);
		vector<int> ans;
		generate_divisors(0, 1, fp, ans);
		return ans;
	}

	vector<long long> get_divisors_full(long long key) {
		vector<pair<long long, long long>> f = factorize_full(key);
		int n = f.size();
		vector<pair<long long, long long>> fp;
		for (auto p : f) fp.push_back(p);
		vector<long long> ans;
		generate_divisors_full(0, 1, fp, ans);
		return ans;
	}


};

int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0);
	
	string s;
	cin >> s;
	int a = 700;
	for (auto ch : s) {
		if (s == 'o') a += 100;
	}
	cout << a << "\n";

	return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:177:23: error: no match for 'operator==' (operand types are 'std::string' {aka 'std::__cxx11::basic_string<char>'} and 'char')
  177 |                 if (s == 'o') a += 100;
      |                     ~ ^~ ~~~
      |                     |    |
      |                     |    char
      |                     std::string {aka std::__cxx11::basic_string<char>}
In file included from /usr/include/c++/14/iosfwd:42,
                 from /usr/include/c++/14/ios:40,
                 from /usr/include/c++/14/ostream:40,
                 from /usr/include/c++/14/iostream:41,
                 from a.cc:1:
/usr/include/c++/14/bits/postypes.h:192:5: note: candidate: 'template<class _StateT> bool std::operator==(const fpos<_StateT>&, const fpos<_StateT>&)'
  192 |     operator==(const fpos<_StateT>& __lhs, const fpos<_StateT>& __rhs)
      |     ^~~~~~~~
/usr/include/c++/14/bits/postypes.h:192:5: note:   template argument deduction/substitution failed:
a.cc:177:26: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::fpos<_StateT>'
  177 |                 if (s == 'o') a += 100;
      |                          ^~~
In file included from /usr/include/c++/14/string:43,
                 from /usr/include/c++/14/bits/locale_classes.h:40,
                 from /usr/include/c++/14/bits/ios_base.h:41,
                 from /usr/include/c++/14/ios:44:
/usr/include/c++/14/bits/allocator.h:235:5: note: candidate: 'template<class _T1, class _T2> bool std::operator==(const allocator<_CharT>&, const allocator<_T2>&)'
  235 |     operator==(const allocator<_T1>&, const allocator<_T2>&)
      |     ^~~~~~~~
/usr/include/c++/14/bits/allocator.h:235:5: note:   template argument deduction/substitution failed:
a.cc:177:26: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::allocator<_CharT>'
  177 |                 if (s == 'o') a += 100;
      |                          ^~~
In file included from /usr/include/c++/14/string:48:
/usr/include/c++/14/bits/stl_iterator.h:441:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator==(const reverse_iterator<_Iterator>&, const reverse_iterator<_Iterator>&)'
  441 |     operator==(const reverse_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:441:5: note:   template argument deduction/substitution failed:
a.cc:177:26: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::reverse_iterator<_Iterator>'
  177 |                 if (s == 'o') a += 100;
      |                          ^~~
/usr/include/c++/14/bits/stl_iterator.h:486:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator==(const reverse_iterator<_Iterator>&, const reverse_iterator<_IteratorR>&)'
  486 |     operator==(const reverse_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:486:5: note:   template argument deduction/substitution failed:
a.cc:177:26: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::reverse_iterator<_Iterator>'
  177 |                 if (s == 'o') a += 100;
      |                          ^~~
/usr/include/c++/14/bits/stl_iterator.h:1667:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator==(const move_iterator<_IteratorL>&, const move_iterator<_IteratorR>&)'
 1667 |     operator==(const move_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1667:5: note:   template argument deduction/substitution failed:
a.cc:177:26: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::move_iterator<_IteratorL>'
  177 |                 if (s == 'o') a += 100;
      |                          ^~~
/usr/include/c++/14/bits/stl_iterator.h:1737:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator==(const move_iterator<_IteratorL>&, const move_iterator<_IteratorL>&)'
 1737 |     operator==(const move_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1737:5: note:   template argument deduction/substitution failed:
a.cc:177:26: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::move_iterator<_IteratorL>'
  177 |                 if (s == 'o') a += 100;
      |                          ^~~
In file included from /usr/include/c++/14/bits/stl_algobase.h:64,
                 from /usr/include/c++/14/string:51:
/usr/include/c++/14/bits/stl_pair.h:1033:5: note: candidate: 'template<class _T1, class _T2> constexpr bool std::operator==(const pair<_T1, _T2>&, const pair<_T1, _T2>&)'
 1033 |     operator==(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_pair.h:1033:5: note:   template argument deduction/substitution failed:
a.cc:177:26: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::pair<_T1, _T2>'
  177 |                 if (s == 'o') a += 100;
      |                          ^~~
In file included from /usr/include/c++/14/bits/basic_string.h:47,
                 from /usr/include/c++/14/string:54:
/usr/include/c++/14/string_view:629:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator==(basic_string_view<_CharT, _Traits>, __type_identity_t<basic_string_view<_CharT, _Traits> >)'
  629 |     operator==(basic_string_view<_CharT, _Traits> __x,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:629:5: note:   template argument deduction/substitution failed:
a.cc:177:26: note:   'std::__cxx11::basic_string<char>' is not derived from 'std::basic_string_view<_CharT, _Traits>'
  177 |                 if (s == 'o') a += 100;
      |                          ^~~
/usr/include/c++/14/string_view:637:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator==(basic_string_view<_CharT, _Traits>, basic_string_view<_CharT, _Traits>)'
  637 |     operator==(basic_string_view<_CharT, _Traits> __x,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:637:5: note:   template argument deduction/substitution failed:
a.cc:177:26: note:   'std::__cxx11::basic_string<char>' is not derived from 'std::basic_string_view<_CharT, _Traits>'
  177 |                 if (s == 'o') a += 100;
      |                          ^~~
/usr/include/c++/14/string_view:644:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator==(__type_identity_t<basic_string_view<_CharT, _Traits> >, basic_string_view<_CharT, _Traits>)'
  644 |     operator==(__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:644:5: note:   template argument deduction/substitution failed:
a.cc:177:26: note:   mismatched types 'std::basic_string_view<_CharT, _Traits>' and 'char'
  177 |                 if (s == 'o') a += 100;
      |                          ^~~
/usr/include/c++/14/bits/basic_string.h:3755:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> bool std::operator==(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 3755 |     operator==(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3755:5: note:   template argument deduction/substitution failed:
a.cc:177:26: note:   mismatched types 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>' and 'char'
  177 |                 if (s == 'o') a += 100;
      |                          ^~~
/usr/include/c++/14/bits/basic_string.h:3772:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> bool std::operator==(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, const _CharT*)'
 3772 |     operator==(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3772:5: note:   template argument deduction/substitution failed:
a.cc:177:26: note:   mismatched types 'const _CharT*' and 'char'
  177 |                 if (s == 'o') a += 100;
      |                          ^~~
/usr/include/c++/14/bits/basic_string.h:3819:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> bool std::operator==(const _CharT*, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 3819 |     operator==(const _CharT* __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3819:5: note:   template argument deduction/substitution failed:
a.cc:177:26: note:   mismatched types 'const _CharT*' and 'std::__cxx11::basic_string<char>'
  177 |                 if (s == 'o') a += 100;
      |                          ^~~
In file included from /usr/include/c++/14/bits/memory_resource.h:47,
                 from /usr/include/c++/14/string:68:
/usr/include/c++/14/tuple:2558:5: note: candidate: 'template<class ... _TElements, class ... _UElements> constexpr bool std::operator==(const tuple<_UTypes ...>&, const tuple<_Elements ...>&)'
 2558 |     operator==(const tuple<_TElements...>& __t,
      |     ^~~~~~~~
/usr/include/c++/14/tuple:2558:5: note:   template argument deduction/substitution failed:
a.cc:177:26: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::tuple<_UTypes ...>'
  177 |                 if (s == 'o') a += 100;
      |                          ^~~
In file included from /usr/include/c++/14/bits/locale_facets.h:48,
                 from /usr/include/c++/14/bits/basic_ios.h:37,
                 from /usr/include/c++/14/ios:46:
/usr/include/c++/14/bits/streambuf_iterator.h:234:5: note: candidate: 'template<class _CharT, class _Traits> bool std::operator==(const istreambuf_iterator<_CharT, _Traits>&, const istreambuf_iterator<_CharT, _Traits>&)'
  234 |     operator==(const istreambuf_iterator<_CharT, _Traits>& __a,
      |     ^~~~~~~~
/usr/include/c++/14/bits/streambuf_iterator.h:234:5: note:   template argument deduction/substitution failed:
a.cc:177:26: note:   'std::string' {aka 'std::__cxx11::basic