PROBLEM with FOR loop (my program does not run, it must start a count in 10 and end in 0)

Basically the conditions you have, you should be more careful when creating your algorithms.

In The First:

for(i=10;i<=0;i--)

your condition looks this way for(i=10;10<=0;i--) condition that if you notice is false ( false ) from the beginning, what you should do is

for(i=10;i>=0;i--)

which looks like: for(i=10;10>=0;i--) which is true (true)

In The Second

for (i=10;i>-1;i--)

your condition becomes true and that's it.

In conclusion, your code should work as follows

#include<stdio.h>

int main() 
{
   int i=0;

   for (i=10;i>=0;i--)

    printf(" %d ",i);

}

to be functional only changes the < (less than) by > (greater than)

so that for read as follows "iterate variable i with initial value of 10, provided it is greater than or equal to 0 and after each iteration subtracts 1 from the value of i"

for (i=10;i<=0;i--) This is a logical error. You are saying that Para i = 10 to 0 increased and decreasing i to 1. One moment, you can not go from one major number to another minor increasing, therefore the comparison is inadequate. Consequently, it is wrong is a sign of a minor. As other users commented, the correct thing would be: for (i=10;i>=0;i--)

As it says @eyllanesc

  

the first field is the one that initializes variables, the second is a conditional, and the third is a task that is carried out when the content is finished

In the first one it does not work since you are saying that you go 10 times the variable i until i (10) is less or = 0 by logic 10 it will never be less or equal to zero, and the second one may work for you already that logic 10 is a positive number and -1 is negative, but it would not make sense to go over the for in that way, possibly it will not show you anything.

Your error is in the condition of the for where it says i