CODEWITHSUNDEEP
c
San
San

Reputation: 11

How to correct multi-character error in C?

Here is what I have tried:

#include<stdio.h>

int main()
{
    int count=0;
    int x;
    char Grade;
    char studentName[50];
    int studentID=0;
    int f=0;

    do
    {
        printf("\nEnter student ID: ");
        scanf("%d", &studentID);

        if(studentID!=0)
        {           
            printf("Enter student name: ");
            scanf("%s", &studentName);
            printf("Enter student marks: ");
            scanf("%d", &x);

            if(x<=100 && x>=80)
                Grade = 'A';
            else if(x<=79 && x>=75)
                Grade = 'A-';
            else if(x<=74 && x>=70)
                Grade = 'B+';
            else if(x<=69 && x>=65)
                Grade = 'B';
            else if(x<=64 && x>=60)
                Grade = 'B-';
            else if(x<=59 && x>=55)
                Grade = 'C+';
            else if(x<=54 && x>=50)
                Grade = 'C';
            else if(x<=49 && x>=45)
                Grade = 'C-';
            else if(x<=44 && x>=40)
                Grade = 'D+';
            else if(x<=39 && x>=35)
                Grade = 'D';
            else if(x<=34 && x>=30)
                Grade = 'D-';
            else if(x<=29 && x>=0)
            {
                Grade = 'F'; 
                f++;
            }   
            printf("%s have the following marks %d and the Grade is %c\n ", studentName, x, Grade);
            count++;        
        }   
    }while(studentID!=0);

    printf("Sum of student =  %d\n", count);
    printf("Sum of fail student = %d\n", f);
}

I get the following error when trying to compile:

"[Warning] multi-character character constant [-Wmultichar]".

I can execute the code but the error keeps bothering me. Also I cannot get the result which have - Grade.

Please advice as I am new learner. Thanks.

Upvotes: 0

Views: 699

Answers (2)

n0p
n0p

Reputation: 3496

As pointed out the error is that you are trying to force 2 char into a variable that can only contain 1, and this is why you cannot have grades with "-", and I guess you don't have those with the "+" neither : it seems that, in your case (cf @mafso comment), the program only takes the 1st char (the letter), the rest is lost.

Let the compiler adjust the size of your containers for you:

// With "[]", the compiler will reserve just what we need
const char * grades[] = 
{
    "F", "D-", "D", "D+", "C-", /* etc... */ "A-", "A+"
};

Also, I think we can do a little mathematical trick to get directly the string-grade from the rating and avoid "waterfall" else if: 

size_t index;

if(x < 25)    // Safety measure
{
    index = 0; // F
}
else if (x > 79) // [edit] ok we need another one
{
    index = 11; // A (or should it be A+ ?)
}
else // The real trick
{
    index = (x/5 + 1) - 6 ;
}

// You need 3 chars: one for the letter, one for the + (or -) and the
// last one for the NULL-terminating '\0' which is the "end-of-string" byte
char student_grade[3];
strcpy(student_grade, grades[index]);

And now you understand why I started grades from "F-" to "A" :)

Upvotes: 2

iqstatic
iqstatic

Reputation: 2382

The error is quite indicative of what is wrong with your code. A multi-character character constant indicates you are trying to assign more than one character to a character constant which is wrong. As pointed by mahendiran.b you cannot assign "A-" or "B-" to Grade as it takes only a single character. It should be a string.

Upvotes: 1

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