1、十进制转换为二进制

/**
十进制转换为二进制
@param decimal 十进制数
@return 二进制数
*/
+ (NSString *)getBinaryByDecimal:(NSInteger)decimal {

　　NSString *binary = @"";
　　while (decimal) {
　　　　binary = [[NSString stringWithFormat:@"%ld", decimal % 2] stringByAppendingString:binary];
　　　　if (decimal / 2 < 1) {
　　　　　　break;
　　　　}
　　　　decimal = decimal / 2 ;
　　　　}

　　if (binary.length % 4 != 0) {
　　　　NSMutableString *mStr = [[NSMutableString alloc]init];
　　　　for (int i = 0; i < 4 - binary.length % 4; i++) {
　　　　　　[mStr appendString:@"0"];
　　　　}
　　　　binary = [mStr stringByAppendingString:binary];
　　}
　　return binary;
}

2、十进制转换为十六进制

/**
将十进制转化为十六进制

@param decimal 10进制 int类型
@return 16进制
*/
+ (NSString*)changDecimalToHex:(NSInteger)decimal {
　　NSString* intDecimalStr = [[NSString alloc] initWithFormat:@"%1lx", (long)decimal];
　　NSString* hexString = [NSString stringWithFormat:@"%@", intDecimalStr];

　　if (hexString.length == 5) {
　　　　return [[NSString stringWithFormat:@"0%@", hexString] uppercaseString];
　　} else {
　　　　return [hexString uppercaseString];
　　}
}

3、 二进制转换为十六进制

/**
 二进制转换成十六进制
   
 @param binary 二进制数
 @return 十六进制数
 */
+ (NSString *)getHexByBinary:(NSString *)binary {
    
    NSMutableDictionary *binaryDic = [[NSMutableDictionary alloc] initWithCapacity:16];
    [binaryDic setObject:@"0" forKey:@"0000"];
    [binaryDic setObject:@"1" forKey:@"0001"];
    [binaryDic setObject:@"2" forKey:@"0010"];
    [binaryDic setObject:@"3" forKey:@"0011"];
    [binaryDic setObject:@"4" forKey:@"0100"];
    [binaryDic setObject:@"5" forKey:@"0101"];
    [binaryDic setObject:@"6" forKey:@"0110"];
    [binaryDic setObject:@"7" forKey:@"0111"];
    [binaryDic setObject:@"8" forKey:@"1000"];
    [binaryDic setObject:@"9" forKey:@"1001"];
    [binaryDic setObject:@"A" forKey:@"1010"];
    [binaryDic setObject:@"B" forKey:@"1011"];
    [binaryDic setObject:@"C" forKey:@"1100"];
    [binaryDic setObject:@"D" forKey:@"1101"];
    [binaryDic setObject:@"E" forKey:@"1110"];
    [binaryDic setObject:@"F" forKey:@"1111"];
    
    if (binary.length % 4 != 0) {
        
        NSMutableString *mStr = [[NSMutableString alloc]init];;
        for (int i = 0; i < 4 - binary.length % 4; i++) {
            
            [mStr appendString:@"0"];
        }
        binary = [mStr stringByAppendingString:binary];
    }
    NSString *hex = @"";
    for (int i=0; i<binary.length; i+=4) {
        
        NSString *key = [binary substringWithRange:NSMakeRange(i, 4)];
        NSString *value = [binaryDic objectForKey:key];
        if (value) {
            
            hex = [hex stringByAppendingString:value];
        }
    }
    return hex;
}

4、十六进制转二进制

/**
 十六进制转换为二进制
 
 @param hexString 十六进制数
 @return 二进制数
 */
+ (NSString *)getBinaryByHexString:(NSString *)hexString {
    NSMutableDictionary *hexDic = [[NSMutableDictionary alloc] initWithCapacity:16];
    [hexDic setObject:@"0000" forKey:@"0"];
    [hexDic setObject:@"0001" forKey:@"1"];
    [hexDic setObject:@"0010" forKey:@"2"];
    [hexDic setObject:@"0011" forKey:@"3"];
    [hexDic setObject:@"0100" forKey:@"4"];
    [hexDic setObject:@"0101" forKey:@"5"];
    [hexDic setObject:@"0110" forKey:@"6"];
    [hexDic setObject:@"0111" forKey:@"7"];
    [hexDic setObject:@"1000" forKey:@"8"];
    [hexDic setObject:@"1001" forKey:@"9"];
    [hexDic setObject:@"1010" forKey:@"A"];
    [hexDic setObject:@"1011" forKey:@"B"];
    [hexDic setObject:@"1100" forKey:@"C"];
    [hexDic setObject:@"1101" forKey:@"D"];
    [hexDic setObject:@"1110" forKey:@"E"];
    [hexDic setObject:@"1111" forKey:@"F"];
    
    NSString *binary = @"";
    for (int i = 0; i < [hexString length]; i++) {
        
        NSString *key = [hexString substringWithRange:NSMakeRange(i, 1)];
        NSString *value = [hexDic objectForKey:key.uppercaseString];
        if (value) {
            
            binary = [binary stringByAppendingString:value];
        }
    }
    return binary;
}

5、十六进制转十进制

/**
 将十六进制转化为十进制
 
 @param hexString 16进制 nsstring类型
 @return 10进制
 */
+ (NSInteger)changHexToDecimal:(NSString*)hexString {
    NSString* temp10 = [NSString stringWithFormat:@"%lu", strtoul([hexString UTF8String], 0, 16)];
    int cycleNumber = [temp10 intValue];
    return cycleNumber;
}

iOS开发进制转换