CS256 - Principles of Structured Design Fall 2021

Displaying ./code/cs256su21code/midtermSol/mtP1sol.txt

This is just the code for the solutions in one text file.

/*

1. Give me a complete program that will print the phrase "I will pass this class."
   and then a newline to the terminal.

*/

#include <stdio.h>

int main(){

	printf("I will pass this class\n");

	return 0;

}

/*
2. 
   Give me code (not a complete program) for a loop that will read integers from user input 
   and will accumulate a sum of all positive even numbers. Terminate that loop when a 
   non-integer is read and output the sum.

   You must declare all variables used in the loop, initialize variables when necessary.

   Hint: You will want to set up your loop so that it will run as long as scanf is still 
         reading integers. Read the C Lesson on the class website if you're not clear on this.

*/

int sum = 0, n;

while (scanf("%d", &n) == 1){
	if(n <= 0) continue;
	if(n % 2 == 0)
		sum = sum + n;
}

printf("sum = %d\n", sum);


/*

3. Write a function named isPrime that takes in a single integer,and returns 1 if the number is prime, and 
   0 if it isn't. If the user enters a 1 or less, have the function return 0
   
   Hint: Recall that Prime Numbers are numbers that have only 2 factors: 1 and themselves. I 
   suggest using a loop going from 2 to (but not including) n and check each number if n % i == 0
   (assuming we're using i as the counting variable). If that statement is true, then we know that
   n isn't prime, so we can go ahead and return 0. If the loop is allowed to completely finish, then 
   we were unable to find a number that divides n, so the number must be prime. If that happens, we 
   return 1.


*/

int isPrime(int n){

   if(n <= 1) return 0;

   for(int i = 2; i < n; i++){
      if(n % i == 0) 
         return 0;
   }

   return 1;

}

/*
4. 
   Consider the following array declaration:

   int numbers[64];

   Assume that the array has been filled with integers. Give me code that sets up a loop that will calculate the 
   average of all the values in that array, then output the average once the loop finishes.
   
   You must declare all variables (other than the already-declared array) used in the loop, initialize variables when necessary.
   You can treat the average as an integer number.

   Hint: If you don't remember, you get the average by dividing the sum of all the numbers by the number of elements.

*/

int sum = 0, avg;

for(int i = 0; i < 64; i++){

   sum = sum + numbers[i];

}

   avg = sum / 64;

   printf("Average value: %d\n", avg);

/*

5. Write a function named charFreq that takes in a character array and a single character, and returns
   an integer that tells us how many times that character appears.

   Hint: This is along the same lines as the myStrlen in the jun22 directory and the charExists in the
         jun15 directory of the in-class code.

*/


int charFreq(char s[], char c){

 int count = 0;

   for(int i = 0; s[i] != '\0'; i++){
      if(s[i] == c) 
         count++;
   }
   
   return count;

}