forループの深さを動的に変える方法

static_loop

for(s_0_0 ; s_0_1 ; s_0_2){
    block_0_0
    for(s_1_0 ; s_1_1 ; s_1_2){
        block_1_0
        for(s_2_0 ; s_2_1 ; s_2_2){
            block_2_0
            block_2_1
        }
        block_1_1
    }
    block_0_1
}

dynamic_loop

const int depth = 3;
int d;
int firstFlg[depth] = {1,1,1};
for(d=0 ;; ){
    if( firstFlg[d] ){
        firstFlg[d] = 0;
        s_d_0;
    }
    if( s_d_1 ){
        block_d_0
        if( d < depth - 1 ){
            ++d;
            continue;
        }
CONTINUE_POINT:
        block_d_1
    }else{
        firstFlg[d] = 1;
        --d;
        if(d == -1){
            break;
        }else{
            goto CONTINUE_POINT;
        }
    }
    s_d_2;
}

sample.c

#include<stdio.h>
#include<stdlib.h>
#include<time.h>

#define MESSAGE_FIRST(d) \
do{ \
	int _i;\
	for(_i=0 ; _i<d ; _i++){ \
		printf("\t"); \
	} \
	printf("s%d_%d\n",d,i[d]); \
}while(0)
#define MESSAGE_LAST(d) \
do{ \
	int _i;\
	for(_i=0 ; _i<d ; _i++){ \
		printf("\t"); \
	} \
	printf("e%d_%d\n",d,i[d]); \
}while(0)

int main(int argc,char *argv[]){
	int *firstFlg;
	int *l;
	int *i; // カウンタ変数
	int depth; // ループの深さ
	int d; //現在のループの深さ

	depth = argc > 1 ? atoi(argv[1]) : 3;

	firstFlg = (int *)malloc(sizeof(int) * depth);
	l        = (int *)malloc(sizeof(int) * depth);
	i        = (int *)malloc(sizeof(int) * depth);

	srand((unsigned)time(NULL));
	for(d = 0 ; d<depth ; ++d){ l[d] = (rand() % 5) + 1; }
	for(d = 0 ; d<depth ; ++d){ firstFlg[d] =  1; }
	
	for(d=0 ;; ){
		if( firstFlg[d] ){
			firstFlg[d] = 0;
			/* s1 */
			i[d] = 0;
		}
		// if( s2 )
		if( i[d] < l[d] ){
			MESSAGE_FIRST(d);
			if( d < depth - 1 ){
				++d;
				continue;
			}
CONTINUE_POINT:
			MESSAGE_LAST(d);
		}else{
			firstFlg[d] = 1;
			--d;
			if(d == -1){
				d = 0;
				break;
			}else{
				goto CONTINUE_POINT;
			}
		}
		/* s3 */
		i[d] += 1;
	}

	free(firstFlg);
	free(i);
	free(l);
	return 0;
}