NSString作业2：取出字符串“123-456-789-000”中的数字部分，组成一个新的字符串输出

#import <Foundation/Foundation.h>

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        NSString *strOriginal=@"123-456-789-000";
        NSRange rang1={0,3},rang2={4,3},rang3={8,3},rang4={12,3};
        NSString *str1=[strOriginal substringWithRange:rang1];
        NSString *str2=[strOriginal substringWithRange:rang2];
        NSString *str3=[strOriginal substringWithRange:rang3];
        NSString *str4=[strOriginal substringWithRange:rang4];
        NSString *strResult=[[NSString alloc]initWithFormat:@"%@%@%@%@",str1,str2,str3,str4];
        NSLog(@"%@ has been change to %@",strOriginal,strResult);
    }
    return 0;
}

#import <Foundation/Foundation.h>

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        NSMutableString *string=[[NSMutableString alloc]initWithFormat:@"123-456-789-000"];
        NSRange rang=[string rangeOfString:@"-"];
        do{
            [string deleteCharactersInRange:rang];
            rang=[string rangeOfString:@"-"];
        }while(rang.location!=NSNotFound);
        NSLog(@"string after chang:%@",string);
    }
    return 0;
}