public static void main(String dfdfd[]){
char c[]=new char[4];
c[0]='+';
c[1]='-';
c[2]='*';
c[3]='/';
for(int i=0;i<4;i++){
for(int i1=0;i1<4;i1++){
for(int i2=0;i2<4;i2++){
for(int i3=0;i3<4;i3++){
System.out.println(""+c[i]+c[i1]+c[i2]+c[i3]);
}
}
}
}
}
组合是随机的吗?如果是的话就用Random随机数
Random ran = new Random();
String str = "";
for (int i = 0; i < 5; i++) {
int a = ran.nextInt(4);
str += a4[a];
}
System.out.println(str);