（转）【iOS 开发】二进制、十进制、十六进制相互转换的方法

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下面罗列了二进制、十进制、十六进制之间相互转换的方法，有时候可能会用的到，需要的朋友可以收藏一下。

---

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

/**
 十进制转换十六进制

 @param decimal 十进制数
 @return 十六进制数
 */
+ (NSString *)getHexByDecimal:(NSInteger)decimal {

    NSString *hex =@"";
    NSString *letter;
    NSInteger number;
    for (int i = 0; i<9; i++) {

        number = decimal % 16;
        decimal = decimal / 16;
        switch (number) {

            case 10:
                letter =@"A"; break;
            case 11:
                letter =@"B"; break;
            case 12:
                letter =@"C"; break;
            case 13:
                letter =@"D"; break;
            case 14:
                letter =@"E"; break;
            case 15:
                letter =@"F"; break;
            default:
                letter = [NSString stringWithFormat:@"%ld", number];
        }
        hex = [letter stringByAppendingString:hex];
        if (decimal == 0) {

            break;
        }
    }
    return hex;
}

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. 十六进制转换为二进制

/**
 十六进制转换为二进制

 @param hex 十六进制数
 @return 二进制数
 */
+ (NSString *)getBinaryByHex:(NSString *)hex {

    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<[hex length]; i++) {

        NSString *key = [hex substringWithRange:NSMakeRange(i, 1)];
        NSString *value = [hexDic objectForKey:key.uppercaseString];
        if (value) {

            binary = [binary stringByAppendingString:value];
        }
    }
    return binary;
}

5. 二进制转换为十进制

/**
 二进制转换为十进制

 @param binary 二进制数
 @return 十进制数
 */
+ (NSInteger)getDecimalByBinary:(NSString *)binary {

    NSInteger decimal = 0;
    for (int i=0; i<binary.length; i++) {

        NSString *number = [binary substringWithRange:NSMakeRange(binary.length - i - 1, 1)];
        if ([number isEqualToString:@"1"]) {

            decimal += pow(2, i);
        }
    }
    return decimal;
}

大概就这么多了，有其他需求可以补充，需要十六进制转换为十进制的话，就按上面方法将十六进制转换为二进制后再转换为十进制就行了，有需要的朋友就收藏一下吧！

http://www.jianshu.com/p/126ebfbd460e