浮点数到C，sprintf中的char数组

Question

I've been googling but I haven't found a simple float to char using the sprintf function. So far - this is all I've written in my small code section. The problem is that I always get a 0 return.

   int main()
   {
        float num_input[9];
        printf("Enter a real number: ");
        scanf("%f", &num_input);
        printf("%f", num_input);
        char str_num[9];
        sprintf(str_num, "%f", &num_input);
        printf(str_num);

        return 0;
    }

Thank you to everyone that helped! I finally saw what I did wrong and learnt more. The final code written was:

float num_input[9];
printf("Enter a real number: ");
scanf("%f", &num_input);
char str_num[9];
int index = 0;
sprintf(str_num, "%f", num_input[index]);

Answer 1

sprintf(str_num, "%f", &num_input); is wrong. You should use something like:

sprintf(str_num, "%f", num_input[index]);  /* 0 <= index < 9 */
/*                    ^          ^^^^^  */

After this keep the fingers crossed that str_num doesn't overflow.

Remember that "%f" specifier of printf family of function should have a matching double or float ( float becomes double after default argument promotion).

---

Perhaps you should make the similar fix for scanf and printf also:

scanf("%f", &num_input[0]);
printf("%f", num_input[0]);