Objextive-C几道小题目笔记

//掷骰子题，掷骰子100次，输出每个号出现的次数

void one()

{

for (int i=1; i<=100; i++) {

int a = arc4random() % 6 +1;

NSLog(@"%d %d",i,a);

}

}

//输出一个字符串中每个字符出现的次数

void two()

{

NSString *str = @"hello apple";

NSMutableDictionary *dic = [NSMutableDictionary dictionary];

for (int i = 0; i < str.length; i++) {

NSRange range = [str rangeOfComposedCharacterSequenceAtIndex:i];

NSString *s = [str substringWithRange:range];

if (dic[s]) {

int count = [dic[s] intValue]+1;

dic[s] = [NSNumber numberWithInt:count];

}else{

dic[s] = @1;

}

}

NSLog(@"%@",dic);

}

//现在有一个有序的数组，要求用户输入一个整数放到数组中还保证这个数组是有序的。例如原数组为@[@1，@3，@5，@7，@9]; 插入8之后为@[@1，@3，@5，@7，@8，@9]

void three()

{

NSArray *arr = @[@1, @3, @5, @7, @9, @8];

NSArray *result = [arr sortedArrayUsingComparator:^NSComparisonResult(NSNumber *obj1, NSNumber *obj2) {

return [obj1 compare:obj2];

}];

NSLog(@"%@",result);

}

//现有如下定义的字符串： NSString *str=@“itheimaAndroid”,能对该字符串进行修改请输出删除Android后的新字符串；

void four()

{

NSString *str1 = @"itheimaAndroid";

NSString *result1 = [str1 stringByReplacingOccurrencesOfString:@"Android" withString:@""];

NSLog(@"%@",result1);

}

//求出1.2.3.4四个数，随意组成一个里面没有相同数字的三位数，总共有多少种组合方式

void five()

{

NSMutableArray *arr = [NSMutableArray array];

for (int i = 1; i <= 4; i++) {

for (int j = 1; j <= 4; j++) {

for (int k = 1; k <= 4; k++) {

if(i != j && i != k && j != k){

[arr addObject:@(i*100 + j*10 +k)];

}

}

}

}

NSLog(@"%@\n%lu", arr, arr.count);

}

//求100以内3的倍数

void six()

{

int i = 1;

NSMutableArray *arr = [NSMutableArray array];

while (i <= 100) {

if (i % 3 == 0) {

[arr addObject:@(i)];

}

i++;

}

NSLog(@"%@\n%lu", arr, arr.count);

}

//深复制，浅复制的问题，随便一个NSArray，用代码创建一个可变和一个不可变数组，他们是深复制还是浅复制

void seven()

{

NSArray *arrary = [NSArray array];

NSArray *a1 = [NSArray arrayWithArray:arrary];

NSArray *a2 = [arrary copy];

NSArray *a3 = arrary;

NSMutableArray *a4 = [NSMutableArray arrayWithArray:arrary];

NSLog(@"\n%p\n%p\n%p\n%p\n%p", arrary, a1, a2, a3, a4);

}

个方法：<1>字符串反转(比如@"123"调用方法后返回@"321")；<2>计算英文字母的个数(比如@"5435abc54abc3AHJ5"调用方法后返回的是9)；<3>去除字符串两端空格(比如@" 1235 45 "调用方法后返回@"1235 45")

- (NSString *)stringByReserve

{

NSMutableString *s = [NSMutableString string];

for (NSUInteger i = self.length; i > 0; i--)

{

[s appendString:[self substringWithRange:NSMakeRange(i-1, 1)]];

}

return s;

}

- (NSUInteger)chararcterCountOfString

{

NSUInteger count = 0;

for (NSUInteger i = 0; i < self.length; i ++)

{

unichar c = [self characterAtIndex:i];

if ((c<='z'&&c>='a')||(c<='Z'&&c>='A')) {

count ++;

}

}

return count;

}

- (NSString *)stringByRemovingBlank

{

return [self stringByReplacingOccurrencesOfString:@" " withString:@""];

}

@import url(http://i.cnblogs.com/Load.ashx?type=style&file=SyntaxHighlighter.css);@import url(/css/cuteeditor.css);