Language: C++

#include <iostream>
#include <algorithm>
#include <cmath>
#include <iomanip>
using namespace std;

typedef long long ll;

ll mod=1e9+7;

ll gcd(ll n,ll m){
    if(m==0) return n;
    else return gcd(m,n%m);
}

ll lcm(ll n,ll m){
    return n/gcd(n,m)*m;
}

bool is_prime(ll n){
    if(n==1) return false;
    else{
        bool ans=true;
        for(ll i=2;i*i<=n;i++){
            if(n%i==0) ans=false;
        }
        return ans;
    }
}

string by_x(ll n,ll x){
    string ans="";
    while(n>0){
        char s=n%x+'0';
        ans=c+ans;
        n/=x;
    }
    return ans;
}

ll order(ll n,ll p){
    ll ans=0;
    while(n%p==0){
        ans++;
        n/=p;
    }
    return ans;
}

//UnionFind
//配列の要素数とかは適宜変える

int parent[100010];
int t_rank[100010];

void init(int n){
    for(int i=0;i<n;i++){
        parent[i]=i;
        t_rank[i]=0;
    }
}

int find(int x){
    if(parent[x]==x) return x;
    else return par[x]=find(par[x]);
}

void unite(int x,int y){
    x=find(x);
    y=find(y);
    if(x==y) return;
    if(t_rank[x]<t_rank[y]) par[x]=y;
    else{
        par[y]=x;
        if(t_rank[x]==t_rank[y]) t_rank[x]++;
    }
}

//mod演算
//ここも配列の要素数とかは適宜変える

void change_mod(ll n){
    mod=n;
}

ll fac[300010];

ll modinv(ll a){
    ll b=mod,u=1,v=0;
    while(b){
        ll t=a/b;
        a-=t*b; swap(a,b);
        u-=t*v; swap(u,v);
        }
        u%=mod;
        if(u<0) u+=mod;
    return u;
}

void modfac(){
    fac[0]=1;
    for(ll i=1;i<300010;i++){
        fac[i]=(fac[i-1]*i)%mod;
    }
}

ll modperm(ll n,ll k){
    if(n<0||k<0||n<k) return 0;
    else return (fac[n]*modinv(fac[n-k]))%mod;
}

ll modcomb(ll n,ll k){
    if(n<0||k<0||n<k) return 0;
    else return ((fac[n]*modinv(fac[k]))%mod*modinv(fac[n-k]))%mod;
}

int main(){
    int a,b,c;
    cin >> a >> b >> c;
    cout << c/a*b << endl;
}

Compiler output:
a.cc: In function 'std::string by_x(ll, ll)':
a.cc:35:13: error: 'c' was not declared in this scope
   35 |         ans=c+ans;
      |             ^
a.cc: In function 'int find(int)':
a.cc:65:17: error: 'par' was not declared in this scope; did you mean '__pstl::execution::v1::par'?
   65 |     else return par[x]=find(par[x]);
      |                 ^~~
      |                 __pstl::execution::v1::par
In file included from /usr/include/c++/14/pstl/glue_algorithm_defs.h:15,
                 from /usr/include/c++/14/algorithm:86,
                 from a.cc:2:
/usr/include/c++/14/pstl/execution_defs.h:43:45: note: '__pstl::execution::v1::par' declared here
   43 | _GLIBCXX17_INLINE constexpr parallel_policy par{};
      |                                             ^~~
a.cc: In function 'void unite(int, int)':
a.cc:72:29: error: 'par' was not declared in this scope; did you mean '__pstl::execution::v1::par'?
   72 |     if(t_rank[x]<t_rank[y]) par[x]=y;
      |                             ^~~
      |                             __pstl::execution::v1::par
/usr/include/c++/14/pstl/execution_defs.h:43:45: note: '__pstl::execution::v1::par' declared here
   43 | _GLIBCXX17_INLINE constexpr parallel_policy par{};
      |                                             ^~~
a.cc:74:9: error: 'par' was not declared in this scope; did you mean '__pstl::execution::v1::par'?
   74 |         par[y]=x;
      |         ^~~
      |         __pstl::execution::v1::par
/usr/include/c++/14/pstl/execution_defs.h:43:45: note: '__pstl::execution::v1::par' declared here
   43 | _GLIBCXX17_INLINE constexpr parallel_policy par{};
      |                                             ^~~