ios進制互相轉換

2to10

NSString *base = @"0110011011001100";
NSLog(@"%@",base);
int i = 0,j = 0;
for (int k = 0; k<base.length; k++) {
    j = [[base substringWithRange:NSMakeRange(k, 1)] intValue];
    j= j *powf(2, base.length-k-1);
    i += j;
}
NSString *base10 = [NSString stringWithFormat:@"%d",i];
NSLog(@"%@",base10);
           

10to16

NSString *base16 = [[NSString alloc]initWithFormat:@"%x",[base10 intValue]];
NSLog(@"%@",base16);
           

16to2

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 *str = [[NSString alloc]init];
    for (int i = 0; i<[base16 length]; i++) {
        NSRange rage;
        rage.length = 1;
        rage.location = i;
        NSString *key = [base16 substringWithRange:rage];
       str = [NSString stringWithFormat:@"%@%@",str,[NSString stringWithFormat:@"%@",[hexDic objectForKey:key]]];
    }
NSLog(@"%@",str);