Generate all the possible substrings using the characters of a given string. 

#import <Foundation/Foundation.h>
@interface PrintStrings: NSObject{
   
}
@end
@implementation PrintStrings{
   
}
-(void)printStr:(NSString*)str index:(int)start{
    int length = [str length];
    if(start>length)
        return;
    for(int i = 0 ; i < length ; i++){
        if(i>0)
        printf("%s ",[[str substringToIndex:i] UTF8String]);
     }
     printf("%s ",[str UTF8String]);
    if(length>1)
    [self printStr:[str substringWithRange:NSMakeRange(start+1,length-1)] index:start];
 
 }
@end
int main(int argc, const char * argv[]){
     
    char a[] = "";
    scanf("%s",a);
    NSString *str = [NSString stringWithFormat:@"%s",a];
    PrintStrings *obj = [[PrintStrings alloc]init];
    [obj printStr:str index:0];
   
    return 0;
}