OC6_字符串练习

//
//  QFString.h
//  OC6_字符串练习
//
//  Created by zhangxueming on 15/6/10.
//  Copyright (c) 2015年 zhangxueming. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface QFString : NSObject

//比如输入 @"abcdef"输出@"fedcba"
+(NSString *)reveserString:(NSString *)srcStr;
//压缩字符串
//比如输入@"aaabbbcceaa" 输出@"3a3b2c1e2a"
+(NSString *)firstContinueString:(NSString *)string;

+(NSString *)compressString:(NSString *)srcStr;

//对字符串按字母顺序进行排序
//比如输入@"aczabczab"  输出@"aaabbcczz"
+(NSString*)sortString:(NSString*)srcStr;

//将原字符串进行小写转大写，大写转小写
//比如输入 @"aBCdEfGA" 输出 @"AbcDeFga"
+(NSString *)reveserCharacters:(NSString*)srcStr;

// 替换字符串srcStr中从startKey到endKey之间的字符串//返回结果
//比如输入srcStr=@"abcdaabbccdef" startKey=@"da" endKey=@"cde" 输出 @"abbc"
+(NSString *)replaceString:(NSString *)srcStr betweenStartKey:(NSString* )startKey  andEndKey:(NSString*)endKey;

// 返回字符串srcStr中出现子串findStr的次数
//helloworldhelloworldhello  hello
+(NSInteger)subStringCount:(NSString*)srcStr findStr:(NSString*)findStr;




+(void)testString;

@end

//
//  QFString.m
//  OC6_字符串练习
//
//  Created by zhangxueming on 15/6/10.
//  Copyright (c) 2015年 zhangxueming. All rights reserved.
//

#import "QFString.h"

@implementation QFString

//@"hello world"
+ (NSString *)reveserString:(NSString *)srcStr
{
    NSUInteger len = [srcStr length];
    NSString *dstString = @"";
    for (NSInteger i=len-1; i>=0; i--) {
        unichar ch = [srcStr characterAtIndex:i];
        dstString = [dstString stringByAppendingFormat:@"%C", ch];
    }
    return dstString;
}
//@"aaabbcccccdddd"
+ (NSString *)firstContinueString:(NSString *)string
{
    NSInteger len = [string length];
    NSInteger i;
    for (i=1; i<len; i++) {
        unichar ch1= [string characterAtIndex:i-1];
        unichar ch2= [string characterAtIndex:i];
        if (ch1 != ch2) {
            break;
        }
    }
    return [string substringToIndex:i];
}
//@"aaabbcccccdddd" --> 3a2b5c4d  @""
+ (NSString *)compressString:(NSString *)srcStr
{
    NSString *dstString = @"";
    NSString *tempStr = srcStr;
    while ([tempStr length]) {
        NSString *subString = [self  firstContinueString:tempStr];
        dstString = [dstString stringByAppendingFormat:@"%ld%C",[subString length], [subString characterAtIndex:0]];
        tempStr = [tempStr substringFromIndex:[subString length]];
    }
    return dstString;
}

+ (NSString *)sortString:(NSString *)srcStr
{
    NSInteger len = [srcStr length];
    for (NSInteger i=0; i<len-1; i++) {
        for (NSInteger j=0; j<len-i-1; j++) {
            unichar ch1 = [srcStr characterAtIndex:j];
            unichar ch2 = [srcStr characterAtIndex:j+1];
            if (ch1 > ch2) {
                srcStr = [srcStr stringByReplacingCharactersInRange:NSMakeRange(j, 1) withString:[NSString stringWithFormat:@"%C", ch2]];
                srcStr = [srcStr stringByReplacingCharactersInRange:NSMakeRange(j+1, 1) withString:[NSString stringWithFormat:@"%C", ch1]];
            }
        }
    }
    return srcStr;
}

//将原字符串进行小写转大写，大写转小写
//比如输入 @"aBCdEfGA" 输出 @"AbcDeFga"
//abcdefga
+(NSString *)reveserCharacters:(NSString*)srcStr
{
    NSString *dstString = [srcStr lowercaseString];
    for (NSInteger i=0; i<[dstString length]; i++) {
        unichar ch = [dstString characterAtIndex:i];
        if ( ch == [srcStr characterAtIndex:i]) {
            dstString = [dstString stringByReplacingCharactersInRange:NSMakeRange(i, 1) withString:[NSString stringWithFormat:@"%C", (unichar)(ch-32)]];
        }
    }
    return dstString;
}

+(NSString *)replaceString:(NSString *)srcStr betweenStartKey:(NSString* )startKey  andEndKey:(NSString*)endKey
{
    
    return nil;
}

// 返回字符串srcStr中出现子串findStr的次数
//worldhelloworldhello  hello
+(NSInteger)subStringCount:(NSString*)srcStr findStr:(NSString*)findStr
{
    NSInteger cnt = 0;
    NSString *tempString = srcStr;
    NSRange range ;
    while ((range = [tempString rangeOfString:findStr],range.location != NSNotFound)) {
        cnt++;
        tempString = [tempString substringFromIndex:range.location+range.length];
    }
    return cnt;
}


+ (void)testString
{
    NSLog(@"%@", [self reveserString:@"hello world"]);
    NSLog(@"%@", [self firstContinueString:@"aaabbcccccdddd"]);
    NSLog(@"%@", [self compressString:@"aaabbcccccdddd"]);
    NSLog(@"%@", [self sortString:@"oiuytredfghjk"]);
    NSLog(@"%@", [self reveserCharacters:@"ASDDsdfsfAFAFA"]);
    NSLog(@"cnt = %li", [self subStringCount:@"helloworldhelloworldhello" findStr:@"hello"]);
}
@end

//
//  main.m
//  OC6_字符串练习
//
//  Created by zhangxueming on 15/6/10.
//  Copyright (c) 2015年 zhangxueming. All rights reserved.
//

#import <Foundation/Foundation.h>
#import "QFString.h"
//4. 现有字符串@"When I was young, I loved a girl on neighbor class."要求不通过点数，从was提取到girl。

//7. 现有字符串@"When I was young, I loved a girl on neighbor class. "从young到girl，改成@"teacher, I rather teaching the students

int main(int argc, const char * argv[]) {
    @autoreleasepool {
#if 0
        NSString *str1 = @"When I was young, I loved a girl on neighbor class.";
        NSRange range1 = [str1 rangeOfString:@"was"];
        NSRange range2 = [str1 rangeOfString:@"girl"];
        if (range1.location != NSNotFound && range2.location != NSNotFound && range2.location > range1.location) {
            NSString *subString = [str1 substringWithRange:NSMakeRange(range1.location, range2.location-range1.location+range2.length)];
            NSLog(@"subString = %@", subString);
        }
        
        NSRange range3 = [str1 rangeOfString:@"young"];
        if (range3.location != NSNotFound && range2.location != NSNotFound && range2.location > range3.location) {
            NSString *str2 = [str1 stringByReplacingCharactersInRange:NSMakeRange(range3.location, range2.location-range3.location+range2.length) withString:@"teacher, I rather teaching the students"];
            NSLog(@"str2= %@", str2);
        }
        
#endif
        [QFString testString];
    }
    return 0;
}