just trash

c_mid.c

#include <stdio.h>

int check_prime(int a)
{
   int c;
   
   for ( c = 2 ; c <= a - 1 ; c++ )
   {
    if ( a%c == 0 ){
      return 0;
    }
   }
  return 1;
}
int maxofthree(int a,int b,int c){
  return a>b && a>c;
}
int minofthree(int a,int b,int c){
  return a<b && a<c;
}

int main(void) {

  // P2. Write a C program that prints out all the Fibonacci numbers between 50 and 100
  int prev_num=21,current_num=34;
  int fibnum = prev_num + current_num;
  while(fibnum > 50 && fibnum<100){
    printf("%d\n",fibnum);
    prev_num = current_num;
    current_num = fibnum;
    fibnum = prev_num + current_num;
  }
  printf("----------------------\n");

  // P3. Write a C program that prints out all the prime numbers between 50 and 100.
  for (int isitprime=50;isitprime<=100;isitprime++){
    if (check_prime(isitprime)){
      printf("%d\n",isitprime);
    }
  }
  printf("----------------------\n");

  // P4. Write a C program that inputs numbers from a file (don't know how many) and calculate the sum of the even numbers only.
  printf("PLEASE CREATE number.txt first!!!\n");
  FILE *fp;
  fp = fopen("number.txt", "r");
  int currrrent_number,moving_sum=0;
  while(fscanf(fp,"%d",&currrrent_number) != EOF )
  {
    if(currrrent_number%2==0){
      moving_sum = moving_sum + currrrent_number;
    }
  }
  printf("Final even sum : %d\n",moving_sum);
  fclose(fp);
  printf("----------------------\n");

  // P5.Write a C program that asks user for a series of numbers (enter -99 to stop) and calculate the average of all the positive numbers only.
  int user_moving_sum=0,user_numer=0;
  while(user_numer!=-99){
    printf("Please input a number: ");
    scanf("%d",&user_numer);
    if(user_numer>0){
      user_moving_sum = user_moving_sum + user_numer;
    }
  }
  printf("Final user sum : %d\n",user_moving_sum);
  printf("----------------------\n");

  // P10.Write an input validation loop that enforces that the number entered by the user is a multiple of 3. Ask the user again if not.
  int the_number_mul_ofthree = -1;
  while(the_number_mul_ofthree%3!=0){
    printf("Please input a number multiple of 3: ");
    scanf("%d",&the_number_mul_ofthree);   
  }
  printf("----------------------\n");

  // P14. Ask a user for three positive integer numbers. Use an input valiadation loop to make sure that all numbers are positive, ask again if not. Determine the smallest, middle and largest number and display them with proper labeling (Smallest=AA, Middle=BB, Largest=CC).
  int usernumber1=-1,usernumber2=-1,usernumber3=-1;
  while(usernumber1<0 || usernumber2<0 || usernumber3<0){
    printf("Please input three POSITIVE number: ");
    scanf("%d%d%d",&usernumber1,&usernumber2,&usernumber3);
  }
  int maxnumber,minnumber;

  if(maxofthree(usernumber1,usernumber2,usernumber3)){
    maxnumber = usernumber1;
  }else if(maxofthree(usernumber2,usernumber1,usernumber3)){
    maxnumber = usernumber2;
  }else{
    maxnumber = usernumber3;
  }

  if(minofthree(usernumber1,usernumber2,usernumber3)){
    minnumber = usernumber1;
  }else if(minofthree(usernumber2,usernumber1,usernumber3)){
    minnumber = usernumber2;
  }else{
    minnumber = usernumber3;
  }
  int middle = usernumber1 + usernumber2 + usernumber3 - minnumber - maxnumber;
  printf("Smallest = %d, Middle = %d, Largest = %d\n",minnumber,middle,maxnumber);

  // P11. Write a C program that implements the following mathematical equation: The summation of 4x + 3x + 2x - x/2 when x is between 1.0 and 5.0 by increments of 0.1 (1.0, 1.1, 1.2 ... 4.9, 5.0). You must use a loop, linear solutions are not acceptable.
  double current_start_num = 1.0;
  double total_sum = 0.0;
  while(current_start_num<=5.0){
    // 4x + 3x + 2x - x/2
    total_sum = total_sum + (4*current_start_num+3*current_start_num+2*current_start_num-current_start_num/2);
    current_start_num = current_start_num + 0.1;
  }  
  printf("Total sum from 0.1 %lf\n",total_sum);

  // P9. We ask the user for positive integer numbers (we don't know how many). Write a complete C program that displays only the numbers that are divisible by either 7 or 11. A negative number acts as a sentinel in this case.
  int post_int = 0;
  while(post_int>=0){
    printf("INPUT NUMBER divisible by 7 or 11\n");
    scanf("%d",&post_int);
    if (post_int%7==0 || post_int%11==0){
      printf("Number : %d\n",post_int);
    }
  }

  printf("END");
  return 0;
}