codice:
#include <stdio.h>
#include <stdlib.h>
#define ARRSIZE(arr) (sizeof(arr)/sizeof(*(arr)))
int main()
{
const char values[]= {'0','1','2','3','4','5','6','7','8','9','a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'};
char * buffer=NULL;
int * stack=NULL;
int combinationLength=-1;
int valuesNumber=-1;
int curPos=0;
fprintf(stderr, "%s", "Length of a combination: ");
if(scanf("%d", &combinationLength)!=1 || combinationLength<1)
{
fputs("Invalid value.\n",stderr);
return 1;
}
fprintf(stderr, "%s (%lu max): ", "Possible digit values",(long unsigned)ARRSIZE(values));
if(scanf("%d", &valuesNumber)!=1 || valuesNumber<1 || (size_t)valuesNumber>ARRSIZE(values))
{
fputs("Invalid value.\n", stderr);
return 1;
}
buffer=(char *)malloc(combinationLength);
stack=(int *)malloc(combinationLength*sizeof(*stack));
if(buffer==NULL || stack==NULL)
{
fputs("Cannot allocate memory.\n", stderr);
free(buffer);
free(stack);
return 2;
}
/* Combinations generator */
for(;;)
{
/* If we reached the last digit symbol... */
if(stack[curPos]==valuesNumber)
{
/* ...get back to the previous position, if we finished exit */
if(--curPos==-1)
break;
/* Repeat this check */
continue;
}
buffer[curPos]=values[stack[curPos]];
/* If we are in the most inner fake-cycle write the combination */
if(curPos==combinationLength-1)
puts(buffer);
stack[curPos]++;
/* If we aren't on the last position, start working on the next one */
if(curPos<combinationLength-1)
{
curPos++;
stack[curPos]=0;
}
}
/* Cleanup */
free(buffer);
free(stack);
return 0;
}
vorrei mi stampasse il risultato in un file .lst nella stessa directory in cui è presente il programma. grazie.