OC 数字对象和字符串对象
一 知识点
二 经典分析
三 （1）数字对象题目针对练习
练习题目1
- (void) t_Number
{
//C中的基本数据类型转化成数字对象
//1)int型
int number = 100;
NSNumber *intNumber = [NSNumbernumberWithInt:number];
NSLog(@"%@ ", intNumber);
//2)char型
char c_number = 'c';
NSNumber *charNumber = [NSNumbernumberWithChar:c_number];
NSLog(@"%@ ", charNumber);
//3)float型
float f_number = 3.14;
NSNumber *flouatNumber = [NSNumbernumberWithFloat:f_number];
NSLog(@"%@ ", flouatNumber);
//4)double型
double d_number = 10.01;
NSNumber *doubleNumber = [NSNumbernumberWithDouble:d_number];
NSLog(@"%@ ", doubleNumber);
//5)bool型
BOOL b_number =NO;
NSNumber * boolNumber = [NSNumbernumberWithBool:b_number];
NSLog(@"%@ ", boolNumber);
}
练习题目2
- (void)t2_Number
{
//数字对象转化成 C中的基本数据类型
//1)int
NSNumber *intNumber;
int i_number = [intNumber intValue];
NSLog(@" %d ", i_number);
//2)char
NSNumber *charNumber;
char c_number = [charNumbercharValue];
NSLog(@"%c ", c_number);
//3)float
NSNumber *floatNumber;
float f_number = [floatNumberfloatValue];
NSLog(@"%f ", f_number);
//4)double
NSNumber *doubleNumber;
double d_number = [doubleNumberdoubleValue];
NSLog(@"%f ", d_number);
//5)bool
NSNumber *boolNumber;
BOOL b_number = [boolNumberboolValue];
NSLog(@"%d", b_number);
//2. 求三个数字对象的最小值(使用对象的compare方法比较)。
[selfcompare_Number];
}
练习题目3
-(void)compare_Number
{
NSNumber *aNumber = [NSNumbernumberWithInt:10];
NSNumber *bNumber = [NSNumbernumberWithInt:50];
NSNumber *cNumber = [NSNumbernumberWithInt:20];
int result1 = [bNumbercompare:aNumber];//b和 a的差
int result2 = [cNumbercompare:aNumber];//c和 a的差
int result3 = [bNumbercompare:cNumber];//b和 c的差
//题目2 //求三个数字对象的最小值(使用对象的compare方法比较)
if ( result1 < 0 && result2 < 0)
{
NSLog(@"aNumber is min ");
}
if( result1 > 0 && result3 >0 )
{
NSLog(@"bNumber is min");
}
if ( result2 < 0 && result2 > 0)
{
NSLog(@"cNumber is min");
}
#if 0
//参考简化
int a, b, c;
if ( a < b && a < c)
{
NSLog(@"a is min");
}
if (b < a && b < c)
{
NSLog(@"b is min");
}
if (c < a && c < b)
{
NSLog(@"c is min");
}
#endif
//题目3求三个数字对象的最大值(使用对象的compare方法比较)。
// a > b && a > c
// b > a && b > c
// c > a && c > b
if ( result1 < 0 && result2 < 0)
{
NSLog(@"a is max");
}
if ( result1 > 0 && result3 > 0)
{
NSLog(@"b is max");
}
if ( result2 > 0 && result3 < 0)
{
NSLog(@"c is max");
}
//4. 求三个数字对象的最大值与最小值(使用对象的compare方法比较)
// a > b && a > c , b > c
// b > a && b > c , a > c
// c > a && c > b, a > b
if ( result1 < 0 && result2 < 0)
{
if ( result3 > 0)
{
NSLog(@"aNumber is max");//a = max
NSLog(@"cNumber is min");//c = min
}else
{
NSLog(@"aNumber is max");//a = max
NSLog(@"bNumber is min");//b = min
}
}
if (result1 > 0 && result3 > 0 )
{
if (result2 < 0)
{
NSLog(@"bNumber is max");//b = max
NSLog(@"aNumber is min");//a = min
}
else
{
NSLog(@"bNumber is max");//b = max
NSLog(@"cNumber is min");//c = min
}
}
if ( result2 > 0 && result3 > 0)
{
if (result1 < 0)//a > b
{
NSLog(@"cNumber is max");//c = max
NSLog(@"bNumber is min");//b = min
}
else
{
NSLog(@"cNumber is max");//c = max
NSLog(@"aNumber is min");//a = min
}
}
}
三 （2）字符串对象题目针对练习
练习题目1
- (void)t_String
{
//NSString字符串 1.使用以下初始化方法： string initWithString: initWithFormat: stringWithFormat:
//分别创建一个字符串对象。
//1)string
NSString * string0 =@"aa";
NSLog(@"%@ ", string0);
//2)initWithString
NSString *string1 = [[NSStringalloc]initWithString:@"bb"];
NSLog(@"%@ ", string1);
//2)initWithFormat
int num = 10;
NSString *string2 = [[NSStringalloc]initWithFormat:@"%d",num];
NSLog(@"%@", string2);
//3)stringWithFormat
int num1 = 20;
NSString *string3 = [NSStringstringWithFormat:@"%d", num1];
NSLog(@"%@", string3);
}
练习题目2
- (void) compare_string
{
//2. 定义三个字符串对象@"hello,string”, @“test”, @“baby”，找出最大字符串与最小字符串并打印出来(使用字符串compare方法)。
NSLog(@"进入字符串比较!!!");
//把字符串对象转化成字符串
NSString *aStr = [[NSStringalloc]initWithString:@"hello,string"];
NSString *bStr = [[NSStringalloc]initWithString:@"test"];
NSString *cStr = [[NSStringalloc]initWithString:@"baby"];
int result1 = [aStrcompare: bStr];//a - b 结果是整型值
int result2 = [aStrcompare: cStr];//a - c
int result3 = [bStrcompare: cStr];//b - c
// a > b && a > c , b > c
// b > a && b > c , a > c
// c > a && c > b, a > b
if ( result1 > 0 & result1 > 0)// aStr is Max
{
if ( result3 > 0)
{
NSLog(@"aStr is max");//aStr = max
NSLog(@"cStr is min");//cStr = min
}else
{
NSLog(@"aStr is max");//aStr = max
NSLog(@"bStr is min");//bStr = min
}
}
if ( result1 < 0 & result3 > 0)// bStr is Max
{
if ( result2 > 0)
{
NSLog(@"bStr is max");//bStr = max
NSLog(@"cStr is min");//cStr = min
}
else
{
NSLog(@"bStr is max");//bStr = max
NSLog(@"aStr is min");//aStr = min
}
}
if ( result2 < 0 & result3 < 0)// cStr is Max
{
if ( result1 > 0)
{
NSLog(@"cStr is max");//cStr = max
NSLog(@"bStr is min");//bStr = min
}
else
{
NSLog(@"cStr is max");//cStr = max
NSLog(@"aStr is min");//aStr = min
}
}
}
练习题目3
- (void) s_string
{
//3. 编写代码举例说明以下字符串方法的使用：
//length
//uppercaseString
//lowercaseString
//capitalizedString
//boolValue
//floatValue
//doubleValue
//intValue
NSLog(@"字符串关键字使用");
//1)length 长度
NSString *str1 = [[NSStringalloc]initWithFormat:@"aaaaa"];
int l_strng = (int)[str1length];
NSLog(@"%d ", l_strng);
//2)uppercaseString || lowercaseString || capitalizedString intValue字符串大小写转换
NSString *str2 =@"bbbbbb";
NSLog(@" %@ ", [str2uppercaseString]);
NSLog(@" %@ ", [str2lowercaseString]);
NSLog(@" %@ ", [str2capitalizedString]);
//3)boolValue || floatValue || doubleValue || intValue || intValue
NSString *str3_b =@" 0 ";
NSLog(@"%d" , [str3_bboolValue]);//转换成BOOL类型
NSString *str3_f =@" 3.14 ";
NSLog(@" %f ", [str3_ffloatValue]);//转换成浮点型
NSString *str3_d =@" 5.12 ";
NSLog(@" %f ", [str3_ddoubleValue]);//转换成双精度
NSString *str3_i =@" 10 ";
NSLog(@" %d ", [str3_iintValue]);//转化成整形
}
练习题目4
- (void)transform_string
{
//4.把字符串@"welcom to yi da hu lian”首字母转换成大写打印输出，全部大写并打印输出，全部小写并打印输出。
NSLog(@"题目4");
NSString *str4 = @"welcom to yi da hu lian";
NSLog(@" %@ ", [str4capitalizedString]);//首字母转换成大写打印输出
NSLog(@" %@ ", [str4uppercaseString]);//全部大写并打印输出
NSLog(@" %@ ", [str4lowercaseString]);//全部小写并打印输出
NSLog(@" %@ ", str4);
}
练习题目5
- (void)separate_string
{
//5.把字符串@"welcom to china,my friends”里的单词全部分离并打印输出.
NSLog(@"题目5");
NSString *str5 = @"welcom to china,my friends";//对象字符串
NSArray *array = [str5componentsSeparatedByString:@","];//字符串对象转化成数组
int cont = (int) [arraycount];
NSLog(@" 5cont =%d ", cont);
for (int i = 0; i < cont ; i++)
{
NSString *str = array[i];
NSLog(@" %@ ", str );
}
}
练习题目6
- (void) separate_string_C
{
//6.编写代码把字符串@"welcom to xcode,hello swift”里的单词分离出，以每个单词首字母大写形式输出。
NSLog(@"题目6");
NSString *str6 =@"welcom to xcode,hello swift";
NSArray *array = [str6componentsSeparatedByString:@","];//先分离字符串转化成数组
int N = (int)[arraycount];
for (int i = 0; i < N; i++)
{
NSString *str = array[i];
NSLog(@" %@ ", [strcapitalizedString]);
}
}
练习题目7
- (void) separate_string_cc
{
//7.把题目6的@"welcom to xcode,hello swift”字符串改成新字符串@"Welcom To Xcode,HELLO SWIFT”并打印输出新字符串。
NSLog(@"题目7");
NSString *str6 =@"welcom to xcode,hello swift";
NSArray *array = [str6componentsSeparatedByString:@","];//先分离字符串转化成数组
for (int i = 0; i < array.count ; i++)
{
if ( i < 1)
{
NSString *str = array[i];
NSLog(@" %@ ", [strcapitalizedString ]);//首字母大写
}
else
{
NSString *str = array[i];
NSLog(@" %@ \n", [struppercaseString]);//全部大写
}
}
}
练习题目8
- (void)str_manipulation
{
//字符串前缀后缀检测/字符串UTF8String编码/单个字符获取
//8. 有一字符串@“http://www.ios.com”,判断字符串是否包含前缀http，是否包含后缀.cn。
NSLog(@"题目8");
NSString * str8 =@"http://www.ios.com";
if ( [str8hasPrefix:@"http"] )
{
NSLog(@"%@包含前缀 %@ ", str8,@"http");
}
else
{
NSLog(@"%@没有包含前缀 %@ ", str8,@"http");
}
if ( [str8hasPrefix:@"cn"])
{
NSLog(@"%@包含 %@后缀 ", str8,@"cn");
}
else
{
NSLog(@"%@没有包含后缀 %@ ", str8,@"cn");
}
}
练习题目9
- (void)str_manipulation9
{
//9. 打印输出@"http://www.ios.com"中包含字符‘i‘,’o’,’s’,’n’对应的所引，找不到则不打印。
NSLog(@"题目9");
//NSString *str9 = @"http://www.ios.com";
NSString *str9 = [[NSStringalloc]initWithFormat:@"http://www.ios.com"];
int strlen = (int)[str9length];//获取字符串长度
NSLog(@"%d ", strlen);
for (int i = 0; i < strlen; i++)
{
char substr = [str9characterAtIndex:i];//获取单个字符
//NSLog(@" %c ", substr);
if ( substr == 'i')
{
NSLog(@"i的索引%d", i);//i的索引
}
if ( substr == 'o')
{
NSLog(@"o的索引%d", i);//o的索引
}
if ( substr == 's')
{
NSLog(@"s的索引%d", i);//s的索引
}
if ( substr == 'n')
{
NSLog(@"n的索引%d", i);//n的索引
}
}
[str9 release];//释放
}
练习题目10
- (void)str_manipulation10
{
//10.写一个字符串加密算法，对字符串对象@"helloboy"进行加密，加密后的密文是@"IFMMPCPZ"，输出该密文。(根据字符的ASCII码可知，小写字母与大写字母数值差为32。即 ‘h'-32就是字符‘H’)
NSLog(@"题目10");
NSString *str10 = [[NSStringalloc]initWithFormat:@"helloboy"];
//NSString *newstr = [str10 uppercaseString];//字符串转化成全部大写
int strlen = (int)[str10length];//字符串长度
for (int i = 0; i < strlen; i++)
{
char substr = [str10characterAtIndex:i] - 31;//通过ANSII表
NSLog(@"%c", substr);
}
[str10 release];//释放
}
练习题目11
- (void)str_cut
{
//11. 把字符串@"thank you very much, my friends!"截取成@"very much, my”，截取成功后把字符串@"dear students!"拼接其后并打印输出。
NSLog(@"题目11");
NSString * str11 =@"hank you very much, my friends!";
NSString * str =@"dear students!";
NSRange str_rang;
str_rang.location = 8;
str_rang.length = 14;
NSString *newstr = [str11substringWithRange:str_rang];//1)实现字符串截取
NSLog(@" %@ ", newstr);
NSString *newstr2 = [newstrstringByAppendingString:str];//2)实现字符串拼接
NSLog(@" %@ ", newstr2);//3)打印输出
}
练习题目12
- (void)str_cut2
{
//12. 有一字符串@“http://www.ioscom”,获取子串@“www.ios.com”并打印输出。
NSLog(@"题目12");
NSString *str12 =@"http://www.ios.com";
NSString *substr = [str12substringFromIndex:7];
NSLog(@" %@ ", substr);
}
练习题目13
- (void)str_cut3
{
//13.把一段英文@“Today is Friday！This is the last weekday！tomorrow is saturday！after saturday is sunday”，编写代码把包含@"day"的单词全部改成大写(比如："Today"包含"day",要把"Today"改成"TODAY")，打印输出改写后的这段新英文。
NSLog(@"题目13");
NSString *str13 =@"Today is Friday! This is the last weekday! tomorrow is saturday! after saturday is sunday";
NSArray *array = [str13componentsSeparatedByString:@" "];//1)分离成每个数组
NSString * newstr = [[NSStringalloc]init];//分配空间
NSString *str_all = [[NSStringalloc]init];//分配空间
for (int i = 0; i < array.count; i++)
{
newstr = array[i];//2)遍历数组赋值给字符串对象
NSRange range = [newstrrangeOfString:@"day"];//3)查询每个包含day
if ( range.location !=NSNotFound)
{
newstr = [newstr uppercaseString];//4)转化成大写
}
str_all = [str_all stringByAppendingFormat:@"%@", newstr];//5)拼接字符串
}
NSLog(@"%@",str_all);
[newstr release];//释放空间
[str_all release];//释放空间
}
练习题目14
- (void)find_string
{
//14. 有一字符串@"welcom to China, My Friends!”，查找字符串@“China”，若存在打印它所在的位置所引，不存在打印 -1。
NSLog(@"题目14");
NSString *str14 =@"welcom to China, My Friends!";
//NSString *substr = @"China";
NSRange range = [str14rangeOfString:@"China"];
if (range.location !=NSNotFound)
{
NSLog(@"location=%ld , length=%ld ", range.location, range.length);
}
else
{
NSLog(@"不存在打印-1");
}
}
练习题目15
- (void)find_str2
{
//15.查找字符串@"today, we will study another string, this string is import for us, now begin the string!"中是否含有@"string",输出它们的所有位置。
NSLog(@"题目15");
NSString *str15 =@"today, we will study another string, this string is import for us, now begin the string!";
NSArray *array = [str15componentsSeparatedByString:@"string"];//分离
int len = (int)[arraycount];//整个字符串对象分离后的的数组长度
int lon0 = 0;int lon1 = 0;int lon2 =0;
for (int i = 0; i < len; i++)
{
NSString *str = array[i];//每次分离的数组转化为每次新的字符串对象
//NSLog(@"str=%@ i= %d@", str, i);//打印出每个分离出的字符串
if ( i == 0 )
{
lon0 = (int)[strlength];//每次字符串的长度
NSLog(@"lon0 = %d", lon0);
}
if ( i == 1)
{
lon1 = (int)[strlength] + lon0;
NSLog(@"lon1 = %d", lon1);
}
if ( i == 2)
{
lon2 = (int)[strlength] + lon0;
NSLog(@"lon2 = %d", lon2);
}
}
}
练习题目16
- (void)delete_str1
{
//16. 删除题目15中@"today, we will study another string, this string is import for us, now begin the string!"所有的@"string"字符串并打印删除后的新英文。
NSLog(@"题目16");
NSMutableString *str16 = [NSMutableStringstringWithString:@"today, we will study another string, this string is import for us, now begin the string!"];//定义可变字符串
NSLog(@"删除string前=%@", str16);
int location = 0, length = 0;
//第一个字符串
NSRange range = [str16rangeOfString:@"string"];
if ( range.location !=NSNotFound)
{
location = (int)range.location;//查询到string的位置
length = (int)range.length;//查询到string的长度
NSLog(@"location=%dlength=%d", location, length);
[str16 deleteCharactersInRange:NSMakeRange(location, length)];//根据查询获取的位置和长度删除string
}
//NSLog(@"删除第1个string%@", str16);
NSRange range1 = [str16rangeOfString:@"string"];
if ( range1.location !=NSNotFound)
{
location = (int)range1.location;//查询到string的位置
length = (int)range1.length;//查询到string的长度
NSLog(@"location=%dlength=%d", location, length);
[str16 deleteCharactersInRange:NSMakeRange(location, length)];//根据查询获取的位置和长度删除string
}
//NSLog(@"删除第2个string%@", str16);
NSRange range2 = [str16rangeOfString:@"string"];
if ( range2.location !=NSNotFound)
{
location = (int)range2.location;//查询到string的位置
length = (int)range2.length;//查询到string的长度
NSLog(@"location=%dlength=%d", location, length);
[str16 deleteCharactersInRange:NSMakeRange(location, length)];//根据查询获取的位置和长度删除string
}
//NSLog(@"删除第3个string%@", str16);
NSLog(@"删除string后=%@", str16);
}
练习题目17
-(void)find_str4
{
//17.在题目15@"today, we will study another string, this string is import for us, now begin the string!"字符串的逗号后面插入字符串@"msn"并打印输出新的英文。
NSLog(@"题目17");
#if 0
//通过可变字符串处理
NSMutableString *str17 = [NSMutableString stringWithFormat:@"today, we will study another string, this string is import for us, now begin the string!"];
NSMutableString *str_all = [NSMutableString string];
NSArray *array = [str17 componentsSeparatedByString:@","];//分离字符串对象
for (int i = 0; i < array.count; i++)
{
[str_all appendFormat:@"%@,msn", array[i]];//逐个追加把@"msn"插入到每个','后面
}
NSLog(@"%@", str_all);
#else
//通过不可变字符串来处理
NSString *str17 =@"today, we will study another string, this string is import for us, now begin the string!";
NSString *str_all = [[NSStringalloc]init];
NSArray *array = [str17componentsSeparatedByString:@","];//分离字符串对象
for (int i = 0; i < array.count-1; i++)
{
str_all = [str_all stringByAppendingFormat:@"%@,msn", array[i]];//添加分离的数组添加msn存放到str_all数组中
}
str_all=[str_all stringByAppendingString:array[array.count-1]];//追加最后面的1个分离出来的数组内容
NSLog(@"%@", str_all);
[str_all release];
#endif
}
练习题目18
- (void)chang_str
{
//NSMutableString可变字符串
//18.定义一个可变字符串@"today, we will study another string, this string is import for us, now begin the string!"，把含有@"string"字符串替换成@"STRING"，打印输出替换后的新英文。
NSLog(@"题目18");
NSMutableString *str18 = [NSMutableStringstringWithString:@"today, we will study another string, this string is import for us, now begin the string!"];
int location = 0;
int length = 0;
NSRange range = [str18rangeOfString:@"string"];
if ( range.location !=NSNotFound)
{
location = (int)range.location;
length = (int)range.length;
[str18 replaceCharactersInRange:NSMakeRange(location, length)withString:@"STRING"];
}
//NSLog(@" %@ ", str18);
NSRange range1 = [str18rangeOfString:@"string"];
if ( range1.location !=NSNotFound)
{
location = (int)range1.location;
length = (int)range1.length;
[str18 replaceCharactersInRange:NSMakeRange(location, length)withString:@"STRING"];
}
//NSLog(@"%@ ", str18);
NSRange range2 = [str18rangeOfString:@"string"];
if ( range2.location !=NSNotFound)
{
location = (int)range2.location;
length = (int)range2.length;
[str18 replaceCharactersInRange:NSMakeRange(location, length)withString:@"STRING"];
}
NSLog(@"%@ ", str18);//处理后打印
}
练习题目19
-(void)delete_str
{
//19.删除题目18中@"today, we will study another STRING, this STRING is import for us, now begin the STRING!"所有@"STRING"字符串,打印输出删除后的新英文。
NSLog(@"题目19");
NSMutableString *str18 = [NSMutableStringstringWithString:@"today, we will study another STRING, this STRING is import for us, now begin the STRING!"];
NSRange range = [str18rangeOfString:@"STRING"];
if ( range.location !=NSNotFound)
{
[str18 deleteCharactersInRange:NSMakeRange(range.location, range.length)];
}
NSLog(@"%@", str18);//删除字符串STRING
NSRange range1 = [str18rangeOfString:@"STRING"];
if ( range1.location !=NSNotFound)
{
[str18 deleteCharactersInRange:NSMakeRange(range1.location, range1.length)];
}
NSLog(@"%@", str18);//删除字符串STRING
NSRange range2 = [str18rangeOfString:@"STRING"];
if ( range2.location !=NSNotFound)
{
[str18 deleteCharactersInRange:NSMakeRange(range2.location, range2.length)];
}
NSLog(@"%@", str18);//删除字符串STRING
}
练习题目20
- (void)insert_str
{
//20. 在题目18字符串的逗号后面插入字符串@"msn"，打印输出新的英文。
NSLog(@"题目20");
NSMutableString *str20 = [NSMutableStringstringWithString:@"today, we will study another string, this string is import for us, now begin the string!"];
NSMutableString *newstr = [NSMutableStringstring];//定义可变字符串
NSArray *array = [str20componentsSeparatedByString:@","];//分离
for (int i = 0; i < array.count; i++)
{
NSString *new_str = array[i];//每个分离出来的字符串存放到新定义的字符串中
[newstr appendFormat:@"%@", new_str];//逐个追加
if ( i != array.count -1)//判断如果是数组最后的元素不插入msn
[newstr insertString:@"msn"atIndex:newstr.length ];//根据每个分离获取新的字符串长度插入msn
}
NSLog(@"20=%@", newstr);
}
练习题目21
- (void)str_encrypt
{
//21.优化之前的字符串加密算法，对字符串对象@"helloboy"进行加密，利用可变字符串接收加密后的密文@"IFMMPCPZ"，打印输出该密文。(根据字符的ASCII码可知，小写字母与大写字母数值差为32。即 'h'-32就是字符'H')
NSLog(@"题目21");
NSMutableString *str = [NSMutableStringstring];//可变字符串
NSString *str21 = [[NSStringalloc]initWithFormat:@"helloboy"];//字符串对象
for (int i = 0; i < str21.length; i++)
{
char c = [str21characterAtIndex:i] - 31;//通过ANSII表
[str appendFormat:@"%c", c];//逐个添加字符
}
NSLog(@"%@", str);
}