# Thread: Calculate and print the average of several grades entered by the user.

1. ## Calculate and print the average of several grades entered by the user.

Here is my code but the problem is that it keeps asking for more than 4 grades, I dont know how to make it stop at 4.

Code:
```#include <stdio.h>

int main()
{

float sum=0,avg;
char letter;
do{
printf ("This program caluculates the average of as many grades you wish to enter.\n\n");
printf("\nFirst, enter the number of grades to process: ");

if(num<2)
printf("\nEnter atleast 2 grades Enter again: ");
}while(num<2);

for(i=0;i<=num;i++)
{
do{
{
printf("\n*** Invalid entry. grade must be 0 to 100. ***:");
i--;
}

}
for(i=0;i<=num;i++)
avg=sum/num;
printf("\nThe average of the %d letter entered is %.2f",num,avg);

if(avg>=90 && avg<=100)
printf(letter,"A");
else if(avg >=80 && avg<=89)
printf(letter,"B");
else if(avg >=70 && avg<=79)
printf(letter,"C");
else if(avg >=60 && avg<=69)
printf(letter,"D");
else if(avg >=0 && avg<=59)
printf(letter,"F");
printf("\nYou have a letter grade of %s\n",letter);
return 0;
}``` 2. Code:
```do{
printf ("This program caluculates the average of as many grades you wish to enter.\n\n");
printf("\nFirst, enter the number of grades to process: ");

if(num<2)
printf("\nEnter atleast 2 grades Enter again: ");
}while(num<2);```
In your if and while statements - what value does the num variable have? 3. I am almost done with my code, I need only a selection structure (if, or if else) statement to check for baddata values.
this is my code so far:
Code:
```#include <stdio.h>int main(){
int n, i;
float num, sum=0.0, average;
printf ("This program caluculates the average of as many grades you wish to enter.\n");
printf("\nFirst, enter the number of grades to process: ");
scanf("%d",&n);
printf ("\nNow enter the %d grades to be averaged.\n\n", n);
for(i=0; i<n; ++i)
{
scanf("%f",&num[i]);
sum+=num[i];
}

average=sum/n;
printf("\nThe average of the 4 grades entered is %.2f\n\n",average);

if(average>=90 && average<=100)
printf("\nYou have a letter grade of A ");
else if(average >=80 && average<=89)
printf("\nYou have a letter grade of B ");
else if(average >=70 && average<=79)
printf("\nYou have a letter grade of C ");
else if(average >=60 && average<=69)
printf("\nYou have a letter grade of D ");
else if(average >=0 && average<=59)
printf("\nYou have a letter grade of F ");

getch ();
}``` Popular pages Recent additions entered, grade, grades, program, user 