Issue with "Grading" Program

I am to create a program that takes data from an input file and assigns a grade basd on averages. The program works great and everything, but I have one issue...

Here is my code:

Code:

/* MAE 9 Final Assignment */

#include <stdio.h>
#include <math.h>

void prob1(void);
void prob2(void);


main()
{
        int menu;
        printf("Enter The Function Number To Execute (1-2): ");
        scanf("%d", &menu);
        switch(menu){
         case 1:
            prob1();
            break;
         default:
            printf("prob%d() does not exist.\n", menu);
        }
        exit(0);
}
void prob1(void)
{
	FILE *infile, *outfile;
	char text[81], ch_grade; 
	double average;
	int lines, k, score [5], i_ave, name[30], last_name[30];
	infile = fopen("score.dat", "r");
	outfile = fopen("grades.dat", "w");
	if(infile == NULL || outfile == NULL){
		printf("***File Opening Error!***\n");
		exit(101);
}
lines=0;
while(fgets(text,81,infile)!=NULL){
	lines++;
	if (lines%2 !=0){
		sscanf(text, "%s %s", 
			name, last_name);
	}else {
		sscanf(text, "%d %d %d %d %d",
			score, score+1, score+2, score+3, score+4);
	for(k=0, average=0.0; k<5; k++)
		average += (double)score[k];
	average /= 5.0;
	i_ave = (int)(average + 0.5);
	if(i_ave = 100) ch_grade = 'A';
	else if(i_ave >= 90) ch_grade = 'A';
	else if(i_ave >= 80) ch_grade = 'B';
	else if(i_ave >= 65) ch_grade = 'C';
	else if(i_ave >= 55) ch_grade = 'D';
	else ch_grade = 'F';
	printf("Student %s %s: ", name, last_name);
	printf("Average = %5.1f;", average);
	printf(" Grade = %c.\n", ch_grade);
	fprintf(outfile, "Student %s %s: ", name, last_name);
	fprintf(outfile, "Average = %5.1f;", average);
	fprintf(outfile, " Grade = %c.\n", ch_grade); 	
	}
	}
	fclose(infile);
	fclose(outfile);
	exit(0);
}

I need the grade of 100% to print out with an "A+", but when I type in the plus I get warning messages. I tried it once just to see and once the plus was in just the first line, all the outputs got changed to just pluses.

Ex:

Student 1, Grade = +
Student 2, Grade = +
and so on...

I only need the 100% student to print out an "A+" what do I need?

Thank you

A bit of confusing code. You are using pointer arithmetic

Code:

average += (double)score[k];

This is not really bad but then later you are calling

Code:

score[k]

Not ideal to jump between styles. You should stay consistent. I could not clearly see where you add the '+' character when you read in a students grades that average 100?

My comment addressing your pointer arithmetic should have showed:

Code:

score, score+1, score+2, score+3, score+4

sorry

Try this

Code:

if(i_ave = 100) ch_grade = "A+";

you declared ch_grade as one character.

Originally Posted by slingerland3g

Try this

Code:

if(i_ave = 100) ch_grade = "A+";

you mean : i_ave == 100

But this won't work since his ch_grade is declared as one character.

Originally Posted by DaveH

you mean : i_ave == 100

But this won't work since his ch_grade is declared as one character.

Yeah, correct. Either change the char to a string variable or simply add a printf statement to append the '+' to the grade within the if block.

Then declare ch_grade as 2 characters.