Why is the function not returning the desired value?

Question

C++ / C#

// I want the function to reset the entered value to a given limit and display the remainder. That is, when we enter 100, when dividing by 25, there is no remainder and 0 comes out, and if 99, then the remainder is 1. Tell me how to arrange? Outputs always "0" for any value.

#include <stdio.h>

int main(void)
{
  int surrender = scanf_s("ENTER...");
  int coin25 = 25,
    coin10 = 10,
    coin5 = 5,
    coin1 = 1;
  int countCoin25 = 0,
    countCoin10 = 0,
    countCoin5 = 0,
    countCoin1 = 0;
  while (coin25 > 0 && surrender - coin25 >= 0) {
    surrender - coin25;
    countCoin25++;
  }
  printf("SURRENDER IS %d " , countCoin25);
  system("pause");
}

Answer 1

• You can reset a variable, but not a value.
  If I understand correctly, and you need to calculate the minimum number of coins, then you need something like this:
  

  #include <iostream>
  
  int main()
  {
      const int N = 4;
      const int coinsValue[N] = {25, 10, 5, 1};
      int coinsCount[N] =       { 0,  0, 0, 0};
  
      int sum;
      std::cin >> sum;
  
      for (int i = 0; i < N; ++i)
      {
          while (sum >= coinsValue[i])
          {
              coinsCount[i]++;
              sum -= coinsValue[i];
          }
          std::cout << coinsCount[i] << " (" << coinsValue[i] << 
          (coinsCount[i] == 1 ? ") coin\n" : ") coins\n");
      }
  
  
  }

Answer 2

int surrender = scanf_s("ENTER...");
int count25 = surrender / 25,
    remainder25 = surrender % 25;
...