Programming-Idioms

History of Idiom 43 > diff from v43 to v44

Edit summary for version 44 :
[C] Clarification of the previous comment (see edit)

Version 43

2019-09-26, 16:45:00

Version 44

2019-09-26, 17:31:27

Idiom #43 Break outer loop

Look for a negative value v in 2D integer matrix m. Print it and stop searching.

Illustration

Idiom #43 Break outer loop

Look for a negative value v in 2D integer matrix m. Print it and stop searching.

Illustration
Imports
#include <stdio.h>
Imports
#include <stdio.h>
Code
int i,j;
for(i=0;i<sizeof(m)/sizeof(*m);i++)
{
	for(j=0;j<sizeof(*m)/sizeof(**m);j++)
	{
		if(m[i][j]<0)
		{
			printf("%d\n",m[i][j]);
			goto end;
		}
	}
}
end:
Code
int i,j;
for(i=0;i<sizeof(m)/sizeof(*m);i++)
{
	for(j=0;j<sizeof(*m)/sizeof(**m);j++)
	{
		if(m[i][j]<0)
		{
			printf("%d\n",m[i][j]);
			goto end;
		}
	}
}
end:
Comments bubble
only works if m is allocated statically or on the stack, not if allocated in the heap.
Comments bubble
only works if m is allocated statically or on the stack, not if allocated in the heap.

edit: the statement above is misleading. It is referring to the use of sizeof() to set up the loops, and has nothing to do with using goto to break the loop. Using goto to break the loop will work as written, regardless of how the variables are allocated.