expression must have integral or unscoped enum type.

#include <iostream>
 #include <iomanip>
 #include <string>
 #include <algorithm>
 #include <sstream>
 
 using namespace std;
 
 int main(){
 
  float size;
 
  float sumNum = 0;
  float maxNum, minNum;
  float mean;
  float totalDev = 0;
  float devSqr = 0;
  float stdDev;
 
  //Create a user input size
  std::cout << "How many number would you like to enter? ";
  std::cin >> size;
  float *temp = new float[size];
 
  //Getting input from the user
  for (int x = 1; x <= size; x++){
  cout << "Enter temperature " << x << ": ";
  cin >> temp[x];
  }
 
  //Output of the numbers inserted by the user
  cout << endl << "Number --- Temperature" << endl << endl;
  for (int x = 1; x <= size; x++){
  cout << " " << x << " --- " << temp[x] << endl;
  sumNum = sumNum + temp[x];
  }
 
  //Calculating the Average
  mean = sumNum / size;
  maxNum = minNum = temp[1];
 
  for (int x = 1; x <= size; x++){
  if (maxNum < temp[x]){
  maxNum = temp[x];
  }
  if (minNum > temp[x]){
  minNum = temp[x];
  }
  }
 
  //Calculating Sample Standard Deviation
  for (int x = 1; x <= size; x++){
  totalDev = totalDev + (temp[x] - mean);
  devSqr = devSqr + (pow((temp[x] - mean), 2));
  }
  stdDev = sqrt((devSqr / (size - 1)));
 
  cout << endl << "The sum: " << sumNum << endl; //the sum of all input
  cout << "The mean: " << mean << endl; //calculate the average 
  cout << "Maximum number: " << maxNum << endl; // print biggest value
  cout << "Minimum number: " << minNum << endl; // print smallest value
  cout << "The range between the maximum and the minimum: " << maxNum - minNum << endl; //the range
  cout << "Deviation: " << totalDev << endl;
  cout << "The squares of deviation: " << devSqr << endl;
  cout << "The Standard Deviation: " << setprecision(1) << fixed << stdDev << endl;
 
  system("pause");
 }