C语言：给定3个字符，输入n,求长度为n的所有组合

Question

C语言：给定3个字符，输入n,求长度为n的所有组合
如给定abc 输入 5，输出aaaaa,abcab 等等

Answer 1

[code="c"]

#include "stdlib.h"
#include "stdio.h"

int strpos=0;

void makeAry(char *buff,int bufflen, char *res,char *tmp,int tmplen,int pos){
int i,j;
for(i=0;i<bufflen;i++){
tmp[pos]=buff[i];
if(pos<tmplen-1){
makeAry(buff,bufflen,res,tmp,tmplen,pos+1);
}
else{
for(j=0;j<tmplen;j++){
res[strpos*tmplen+j]=tmp[j];
}
strpos++;
}
}
}

int main(int argc, char* argv[])
{
int i,j;
char buff[3];
printf("Please input three letter:",buff);
gets(buff);
char buff2[10];
printf("Please input a number:",buff2);
gets(buff2);
int len = atoi(buff2);
long reslen = 3;
for(i=0;i<len-1;i++){
reslen*=3;
}
char res = (char)malloc(reslen*len);
char tmp = (char)malloc(len);
makeAry(buff,3,res,tmp,len,0);
printf("It's %i groups:\n",reslen);
for(i=0;i<reslen;i++){
for(j=0;j<len;j++){
printf("%c",res[len*i+j]);
}
printf("\n");
}
return 0;
}
[/code]