tableaux

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#define DIM 1000

int clear_input_buffer(void)
{
    int ch;
    while(((ch = getchar()) != EOF) && (ch != '\n')) /* void */
	;
    return ch;
}

int main(int argc, char** argv)
{

    int reponse;

    do {
	printf("choose: \n 1: td 3 n 4 \n 2: td 3 n 6 \n 3: td 3 n 7 \n");
	scanf("%d", &reponse);
    } while(reponse != 1 && reponse != 2 && reponse != 3);

    if(reponse == 1) {

	int i, j;
	char phrase[DIM], phrase1[DIM];

	printf("entrez une phrase\n");
	scanf("%s", phrase);
	int len = strlen(phrase);
	for(i = 0; i < len; i++) {
	    phrase1[i] = phrase[i];
	}

	printf("combien de permutations de positions voulez vous faire ? maximum : %d \n", len);

	do {
	    scanf("%d", &reponse);
	} while(reponse < 0 || reponse >= len);

	for(i = 0, j = 1; i < reponse; i++, j++) {
	    /*
	    //avec un tableau secondaire
	phrase[i] = phrase1[j];
	phrase[j] = phrase1[0];
	    */

	    // sans un tableau secondaire
	    phrase[i] = phrase[j];
	    phrase[j] = phrase[0];

	    printf("%s \n", phrase);
	}

	printf("le resultat final: %s", phrase);
    }

    if(reponse == 2) {

	clear_input_buffer();
	char phrase[DIM];
	int i, j;

	printf("entrez une phrase:\n");

	gets(phrase);
	int len = strlen(phrase);

	for(i = len; i >= -1; i--) {
	    if(phrase[i] == 32 || i == -1) {
		for(j = i + 1; j < len; j++) {
		    printf("%c", phrase[j]);
		    if(phrase[j] == 32)
			break;
		}
		printf(" ");
	    }
	}
    }

    if(reponse == 3) {

	clear_input_buffer();
	char phrase[DIM];
	int i, j, nbDeMots = 1;

	printf("entrez une phrase:\n");
	gets(phrase);
	int len = strlen(phrase);

	for(i = 0; i < len; i++) {
	    if(phrase[i] == 32) {
		nbDeMots++;
	    }
	}
	printf("\nIl y a %d mots.", nbDeMots);
    }
}