Thread: What is wrong program not calculating correctly.

I cannot figure what I have done wrong but it does not go through the calculations. It just displays 0.

Code:

Code:

#include <iostream>
#include <cstdlib>         
#include <stdio.h>
#include <cmath>
#include<fstream>


double Homework ( double homework); // fuction for homework weight
double Midterm ( double midterm); // function for midterm weight
double Final ( double final);     // function for final test weight
//function to calculate final grade
double CalcGrade (double homework, double midterm, double final, double totalScore, char grade);
//function to print 
int Print( double homework, double midterm, double final, double totalScore, char grade);


int main()
{
    //local delcarations
    double homework;
    double midterm;
    double final;
    double totalScore;
    char grade;
    
    //informs the user what this program does
    printf("This program will calculate the final grade after homework\n");
    printf("midterm, and final test grades are inputed in.\n");
    system("cls"); //clears screen
    
    //function calls
    Homework(homework);
    Midterm(midterm);
    Final(final);
    CalcGrade ( homework,  midterm,  final,totalScore, grade);
    Print(homework, midterm, final, totalScore, grade);




system("pause"); //holds screen for dev C++


return 0;
}  //end of main


/////////////////////////////HOMEWORK////////////
double Homework (double homework)
{
system("cls");


//function delcarations
int x ;
int i ;
double sum;
double homeworkMaxPts ;
// homework ;


//prompts users for input, and how to terminate
printf("Enter the homework assignment grades: \nEnter < 999 > to stop.\n");


do //loop to collect input for homework grades
{
      scanf("%d", &x);
      if ( x <900) //termination of loop
      sum += x; // calculated total amount of points
}while ( x < 900);


//prompts user to input maxmum score for each assignment
printf("Enter the max points for each assignemnt: \n");
printf("Enter < 999 > to stop\n ");


//loop to collect imput for maximun points possible for homework
do
{
            scanf("%d", &i);
            if ( i < 900) //loop termination
            homeworkMaxPts += i; // calculates total amount of points
}while ( i < 900);


//calculates the total weight of homework
homework =(sum*50/homeworkMaxPts); 




system("pause"); 
 return homework; // returns weighted homeword


}      //end of homework


// Function to determine weight of midterm tests
double Midterm ( double midterm)
{


system("cls"); // clear screen


//declarations
int a=0;
int i=1;
double sum;
int x =1;
double midMaxPts = 0;
int b=0;
 //midterm =0;


// prompts user to input midterm grades
printf("Enter the midterm grades: \n");


//loop to calculate total midterm points
while(i<=3)
{
           scanf("%d", &a);
           sum +=a;
           i++;
}//end of while
//prompts user to imput maximun amount of points possible
printf("\nEnter the max points for midterm grades: \n");


//loop to calculate total possible points
while ( x <=3)
{
      scanf("%d", &b);
      midMaxPts += b;
      x++;
}//end of while


system("cls"); //clear screen
midterm = (sum*20/midMaxPts); //calculate midterm weights








    
 system("pause");
 return midterm; //return midterm


} //end of midterm


//Final test function
double Final ( double final)
{


system("cls"); //clear screen
//declarations
int final1, final2; 
int finalSum = 0;
int points1, points2;
double finalMaxpts = 0;
final = 0;
//prompts user to input the two final grades
printf("Enter the final grades: \n" );
scanf("%d %d", &final1, &final2);
//prompts user to input the maximum points for finals
printf("Enter the max points possible for each grade: \n");
scanf("%d %d", &points1, &points2);


finalSum = final1 + final2; //calculates total points made


finalMaxpts = points1 + points2; //calculates total points possible


final = (finalSum*30/finalMaxpts); //calculates weight of final


 system("cls");
 system("pause");
 return final; // returns final weight
} //end final function


// grade calculation function
double CalcGrade (double homework, double midterm, double final, double totalScore, char grade)
{
    //calculate final overall grade
    totalScore = homework + midterm + final;
    
    //to calculate the letter grade
    if (totalScore >= 90)
       grade = 'A';
    else if ( totalScore >= 80)
         grade = 'B';
    else if ( totalScore >= 70)
         grade = 'C';
    else if ( totalScore >= 60)
         grade = 'D';
    else 
         grade = 'F';
         
system("pause");
return grade; //return grade
} 


  // print function                                                       
int Print( double homework, double midterm, double final, double totalScore, char grade)
{
// prints out all grades
printf("\n\nFinal exam score was %2.2f\n", final);
printf("Midterm exam score was %2.2f\n", midterm);
printf("Homework assignments score were %2.2f\n", final);
printf("------------------------------------------\n\n");
printf("Total score is %2.2f\n", totalScore);
printf("Grade for the class is %c\n\n\n", grade);


system("pause");


return 0;
}        //

You should probably decide first if you want to write C++ or C code, pick one then go with that. Then post in the correct forum and maybe someone will help you out, if it isn't homework. maybe.

In the Homework function, at least, you've prototyped it to take a double as an argument and return a double. When you call the function in main, you're passing in an uninitialized copy and not using the returned value.

Code:

double Homework(double);
...
double homework;
...
Homework(homework);

the other value returning functions are similar. that is, you're passing in uninitialized copies and you don't do anything with the value they return.

When you call Print, changes that were made to your locals (homework, midterm, final, etc) were left behind in the functions because you passed them by value; the value returned by the functions was probably suspect anyway.

I'm not sure why you're passing in the variables. Unless it's required, you'd probably be better off making the functions take no arguments and use the locals to get the returns. Or make the functions return no value and pass in the locals by reference.

Code:

int x;
double sum;

do //loop to collect input for homework grades
{
      scanf("%d", &x);
      if ( x <900) //termination of loop
      sum += x; // calculated total amount of points
}while ( x < 900);

have you disabled compiler warnings??