NSMultableString的基本用法

#import 

int main(int argc, const char * argv[]) {
    
    
    //---------------NSMutableString   可变字符串--------------
    
    //创建
    NSMutableString *s1 = @"wxhl";  //创建的是不可变的字符串
    
    //预留5个字符的空间，可以扩展
    NSMutableString *s2 = [[NSMutableString alloc] initWithCapacity:5];
    //alloc
    NSMutableString *s3 = [[NSMutableString alloc] initWithFormat:@"123"];
    //类方法
    NSMutableString *s4 = [NSMutableString stringWithFormat:@"abc"];
    
    
    //---------------NSMutableString特有的方法--------------
    //1.插入字符串
    [s3 insertString:s4 atIndex:0];
    NSLog(@"s3 = %@",s3);
    
    //不可变字符串不可以改变
    //[s1 insertString:s2 atIndex:0];
    
    //2.删除字符串
    NSRange range = {0,3};
    [s3 deleteCharactersInRange:range];
    NSLog(@"s3 = %@",s3);
    
    //3.追加字符串
    [s3 appendString:s4];
    NSLog(@"s3 = %@",s3);
    
    [s3 appendFormat:@"fghj"];
    NSLog(@"s3 = %@",s3);


    return 0;
}