2. Constant is a quantity that cannot be changed during the whole program running. (right)
3. Empty statements are not allowed in C language. You can test yourself and try to write more semicolons.
4. In Standard C, programming must be annotated. (Wrong) It depends on the individual.
5. In standard C, the statement must use ";" Mark over. A semicolon marks the end of the sentence body.
6. If the integer variables I, J, k J, K, I = 4 and J = 5 are set, then k=0.8 after I/J operation. (Wrong) Integer divisibility, k=0
7. In the process of logical operation, not all expressions are solved. (Yes) There is a short circuit principle, such as: a =1; b = 3； In a logical statement (a=a+b)! =0||(a=a- 1)！ =0, it has been confirmed (a=a+b)! =0 is true, and the statement after the || symbol is not solved.
8. The three basic structures of C language programs are sequence structure, selective structure and cyclic structure. (right)
9, programming should first pay attention to the execution efficiency of the program, followed by readability. () I'm not sure about this either. I think it's right.
10 and 5++ are legal expressions. (Error) Constant cannot be changed.
2. Print out the following patterns.
*
* * *
* * * * *
* * * * * * *
* * * * *
* * *
*
# include & ltstdio.h & gt
int main()
{
int i，j；
for(I = 0； I<4; i++)
{
for(j = 0； j & lt 14-I； j++)
printf(" ")；
for(j = 14-I； j & lt 14-I+2 * I+ 1； j++)
printf(" * ")；
printf(" \ n ")；
}
for(I = 3； I & gt=0; I-)
{
for(j = 0； j & lt 14-I； j++)
printf(" ")；
for(j = 14-I； j & lt 14-I+2 * I+ 1； j++)
printf(" * ")；
printf(" \ n ")；
}
Returns 0;
}