一旦程序开始运行，这个循环就不会结束

Question

Once my program starts running it is not stopping after few steps. Can anyone help me with this?

#include <stdio.h>
void main()
{
   int n,row,column,lim1,lim2,k;
   scanf("%d",&n);
   lim2=(2*n)-1;
   lim1=1;
   k=n;
   for(row=1,column=1;row<=lim2,column<=lim2;row++,column++)
      while((row||column=lim1)||(row||column=lim2))
      { printf("%d",k);
        n--;
        lim1=lim1+1;
      }
}

Answer 1

Expressions of the form

(row||column=lim1)

do not mean anything like what you appear to think they mean.

In the first place, the column=lim1 part is an assignment , not an equality test. Equality tests use the == operator. On the other hand, in C, assignments are expressions (they evaluate to the value assigned), so they may appear as sub-expressions of larger expressions, as here. In boolean context, the value zero represents false, and any other value represents true. lim1 starts at 1 and counts up, so its value never evaluates to true (unless it counts up so far that it wraps back to zero).

But the more significant issue is the use of the ||operator. My best guess is that you mean the above excerpt to express a condition that either row or column is equal to lim1 , but it doesn't mean that at all. Instead, it expresses the condition that either row is nonzero ( ie true) or the result of column=lim1 is nonzero. Since row starts at 1 and is not modified in the inner loop, that overall expression will always evaluated to true.

Moreover, C guarantees that if the left-hand operand of an ||operator evaluates to true, then the right-hand operand isn't even evaluated (since that is not needed to determine the result of the operation).

The condition you seem to want to express could be spelled like this:

((row == lim1) || (column == lim1))

Similar changes are needed in the other half of the inner loop's condition.