C中输入数字的平均值-总和始终为0

Question

Here is a code which evaluates the average of 10 entered numbers. Problem is it doesn't seem to print the sum correctly (it's always equal to 0) after exiting the loop, everything else is working fine.

int count=0, n=10, c;
float sum=0, x;
do{
    printf("x=");
    scanf("%f", &x);
    count++;
    sum+=x;
}
while(count<n);
printf("Sum is %d", sum);
printf("\nCount is: %d", count);
printf("\nThe Average of the numbers is : %0.2f", sum/count);
getch();
}

Another question is how to exit the loop after a symbol is reached(ie without setting a limit to the number of integers to be entered).

Answer 1

Use the %f format specifier for floating point numbers.

printf("Sum is %f", sum);

To exit the loop on a symbol, you could check the return value from scanf . scanf returns the number of items read. If it returns 0 then the user didn't type a valid number.

while (1) {
    printf("x=");

    if (scanf("%f", &x) != 1) {
        break;
    }

    ...
}

break exits the current loop.

Answer 2

To answer your first question it should be printf("%f",sum) to print the correct sum. Since you are using float you have to use %f, if you use int it is %d. For your second question, you can do something like this (modify it accordingly):

int main(){ 
// Declare Variables 
int count = 0; float sum = 0, currentNum = 0;

// Ask user for input 
while(currentNum > -1)
{ 
   printf("Enter integer to be averaged (enter -1 to get avg):"); 
   scanf("%f",&currentNum); 
   if(currentNum == -1)
       break; 

   // Check the entered number and computed sum
   printf("You entered: %0.2f\n", currentNum); 
   sum += currentNum; 
   printf("Current sum: %0.2f\n", sum);
   count++; 
}

// Print Average
printf("Average is: %0.2f\n", sum/count); 

return 0; 
}

Answer 3

To answer your second question, you could do this:

scanf("%f", &x);
if (x==0) {
  break;
}

This will break you out of the loop if you enter 0, then your loop can be infinite:

do {

} while(true)

Answer 4

对于第二个问题，我认为EOF可能是更好的解决方案：

while(scanf("%f", &x) != EOF)