在C中使用赋值语句进行循环条件

Question

Is statement A & B are equal?

int i;
char a[] = "Hello\n";
char b[100];    

Statement A,

for(i=0; b[i] != '\0'; ++i)
    b[i] = a[i];

Statement B,

for(i=0; (b[i] = a[i]) != '\0'; ++i)
      ;

Answer 1

No, they are different:

• The first loop checks the value of b[i] before the assignment;
• The second loop checks the value of b[i] after the assignment.

As the result, the second loop will copy the content of a into b , and stop after copying \\0 . The first loop would stop copying as soon as it encounters the first \\0 in b before performing a copy, disregarding any zeros that it may find in a .

Answer 2

No they are not.

In statement A, you are checking b[i] before assigning value to it

In the second statement, you are assigning value before checking.

The 1st one is like a while loop , where is the second one is like a do - while loop .

Answer 3

NO they are not the same

in the second you have set the b[i] value and then you have checked != '\\0' .

in the fisrt you have checked the b[i] != '\\0' before set it

I can suggest to you also:

int i = -1;
while(b[++i] = a[i]);