The result of the expression s++ is the value of s *before* the increment, so the expression (s++ < 10) operates on the values 0 through 9.
In the body of the loop, s has been incremented, so the expression (s < 4 && s < 9) operates on the values 1 through 10. When s is between 1 and 3, the continue statement is executed and the loop repeats from the beginning, skipping the printf. So only the values 4 through 10 are written to standard output.
Nits: unless your compiler documentation *explicitly* lists void main() as a legal signature, use int main(void) instead.
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