C scanf ignore second variable in loop [duplicate] - c

Question

This question already has answers here:
What is the effect of trailing white space in a scanf() format string?
(4 answers)
Why does scanf ask twice for input when there's a newline at the end of the format string?
(7 answers)
Closed 3 years ago.
int main()
{
float T[100];
float *pt=T;
float suma = 0, srednia, zmienna;
int rozmiar;
printf("How many numbers would you like to put in: ");
scanf(" %d", &rozmiar);
int dzielnik = rozmiar;
printf("\n Enter the number: \n");
for(int i = 0;i<rozmiar;i++)
{
printf("\n i = %d", i );
scanf("%99f\n", &zmienna);
*(pt+i) = zmienna;
}
return 0;
}
This is my code. The idea is simple. I have an array; I want to scan how many numbers I want to put into the array and then put numbers into array. I don't know why but scanf ignores the second variable that I put in array.
If I put "2" in first scanf, program wants 3 variables from me.
My output should be like this:
How many numbers would you like to put in: 2
Enter the number:
i = 0
2 (my number)
i=1
3 (my number)
but it's actually like this:
How many numbers would you like to put in: 2
Enter the number:
i = 0
1 (my number)
2 (my number)
i = 1
3 (my number)

Answer 1

The specific problem you were having is with scanf: putting a \n is generally a bad idea because entering a newline is generally how you send off a line of characters to the program. Use '\n' liberally in printf and "never" with scanf.
Here's my modified version. I removed the pointer shenanigans because indexing into the array is simpler and better, and also initialized the array which you should always do:
#include <stdio.h>
int main() {
float T[100] = {0}; // Used to not be initialized.
float suma = 0, zmienna;
int rozmiar;
printf("How many numbers would you like to put in: ");
scanf("%d", &rozmiar);
printf("\n Enter the number: \n");
for (int i = 0; i<rozmiar; i++) {
printf("\n i = %d", i);
scanf("%f", &zmienna);
T[i] = zmienna;
}
return 0;
}