Simple for-loop countdown timer in C

Question

This is what the code should do:

“Lift off in T minus
5
4
3
2
1
Blast-off!”

When I run it, it just keeps printing ''Sum = 5'' forever.

Code:

int main(void) {

int sum = 5;  
int i;     

printf("Lift off in T minus\n");

for (i = 0; i < 5; i=i+i) {
    sum = sum - i;  
    printf("sum = %d\n",sum);  
} 

printf("Blast-off",sum);  

return 0;

Answer 1

for (i = 0; i < 5; i=i+i) { // use i = i+1
    sum = sum - i;       //sum-- or sum = sum -1
    printf("sum = %d\n",sum);  
} 

As initially i=0, so

i=i+i; //will be zero always, no increment.

And

sum = sum -1;

otherwise

i = 0  =>sum = sum - i;    // = 5 as i=0
i = 1  =>sum = sum - i;    // = 4 as i=1
i = 2  =>sum = sum - i;    // = 2 as i=2
i = 3  =>sum = sum - i;    // = -1 as i=3