首先了解系统方法
/**
C字符串转无符号长整型
@param __str C字符串
@param __endptr 对类型为 char* 的对象的引用，其值为__str停止转换的下一个字符
@param __base C字符串的进制 2~36
@return 无符号长整型
*/
unsigned long strtoul(const char *__str, char **__endptr, int __base);
strtoul 栗子
// 二进制字符串转整型
NSString *binary = @"1101";
char *endpth;
NSUInteger decimal = strtoul([binary UTF8String], &endpth, 2);
NSLog(@"decimal:%li, endpth:%@", decimal, [NSString stringWithUTF8String:endpth]);
输出:
2018-06-04 17:01:44.836182+0800 ZXXTestDemo[30806:2638721] decimal:13, endpth:
// 十六进制字符串转整型
NSString *hex = @"0X1A";
char *endpth;
NSUInteger decimal = strtoul([hex UTF8String], &endpth, 16);
NSLog(@"decimal:%li, endpth:%@", decimal, [NSString stringWithUTF8String:endpth]);
输出:
2018-06-04 17:07:38.029495+0800 ZXXTestDemo[31055:2666063] decimal:26, endpth:
// 字符串有误时, 可以根据 endpth 进行判断
NSString *binary = @"1121";
char *endpth;
NSUInteger decimal = strtoul([binary UTF8String], &endpth, 2);
NSLog(@"decimal:%li, endpth:%@", decimal, [NSString stringWithUTF8String:endpth]);
输出:
2018-06-04 17:08:11.607153+0800 ZXXTestDemo[30940:2653669] decimal:3, endpth:21
但是居然没有与 strtoul 对应的 ultostr 方法, so 就自己写了一个类似的方法
/**
无符号长整型转C字符串
@param num 无符号长整型
@param base 进制 2~36
@return C字符串
*/
char *ultostr(unsigned long num, unsigned base) {
static char string[64] = {'\0'};
size_t max_chars = 64;
char remainder;
int sign = 0;
if (base < 2 || base > 36) {
return NULL;
}
for (max_chars --; max_chars > sign && num != 0; max_chars --) {
remainder = (char)(num % base);
if ( remainder <= 9 ) {
string[max_chars] = remainder + '0';
} else {
string[max_chars] = remainder - 10 + 'A';
}
num /= base;
}
if (max_chars > 0) {
memset(string, '\0', max_chars + 1);
}
return string + max_chars + 1;
}
ultostr 栗子
// 整型转二进制
NSUInteger decimal = 15;
char *binary = ultostr(decimal, 2);
NSLog(@"binary:%@", [NSString stringWithUTF8String:binary ? : "\0"]);
输出:
2018-06-04 17:25:46.674484+0800 ZXXTestDemo[31246:2693033] binary:1111
NSUInteger decimal = 15;
char *hex = ultostr(decimal, 16);
NSLog(@"hex:%@", [NSString stringWithUTF8String:hex ? : "\0"]);
输出:
2018-06-04 17:28:29.335201+0800 ZXXTestDemo[31318:2700423] hex:F
strtoul:任意进制的字符串可以转整型, ultostr:整型又可以转任意进制字符串, 那么进制间的转换就 so easy
以下是常用的进制转换
@interface NSString (ZXXExtension)
/// 十进制转二进制
+ (NSString *)getBinaryByDecimal:(NSInteger)decimal;
/// 二进制转十进制
+ (NSInteger)getDecimalByBinary:(NSString *)binary;
/// 十六进制转十进制
+ (NSInteger)getDecimalByHex:(NSString *)hex;
/// 十进制转十六进制
+ (NSString *)getHexByDecimal:(NSInteger)decimal;
/// 十六进制转二进制
+ (NSString *)getBinaryByHex:(NSString *)hex;
/// 二进制转十六进制
+ (NSString *)getHexByBinary:(NSString *)binary;
@end
#import "NSString+ZXXExtension.h"
@implementation NSString (ZXXExtension)
/**
无符号长整型转C字符串
@param num 无符号长整型
@param base 进制 2~36
@return C字符串
*/
char *ultostr(unsigned long num, unsigned base) {
static char string[64] = {'\0'};
size_t max_chars = 64;
char remainder;
int sign = 0;
if (base < 2 || base > 36) {
return NULL;
}
for (max_chars --; max_chars > sign && num != 0; max_chars --) {
remainder = (char)(num % base);
if ( remainder <= 9 ) {
string[max_chars] = remainder + '0';
} else {
string[max_chars] = remainder - 10 + 'A';
}
num /= base;
}
if (max_chars > 0) {
memset(string, '\0', max_chars + 1);
}
return string + max_chars + 1;
}
/// 十进制转二进制
+ (NSString *)getBinaryByDecimal:(NSInteger)decimal {
char *hexChar = ultostr(decimal, 2);
NSString *binary = [NSString stringWithUTF8String:hexChar];
return binary;
}
/// 二进制转换为十进制
+ (NSInteger)getDecimalByBinary:(NSString *)binary {
char *endptr = "";
NSInteger decimal = strtoul([binary UTF8String], &endptr, 2);
if (strlen(endptr)) {
return 0;
}
return decimal;
}
/// 十六进制转换十进制
+ (NSInteger)getDecimalByHex:(NSString *)hex {
char *endptr = "";
NSInteger decimal = strtoul([hex UTF8String], &endptr, 16);
if (strlen(endptr)) {
return 0;
}
return decimal;
}
/// 十进制转换十六进制
+ (NSString *)getHexByDecimal:(NSInteger)decimal {
char *hexChar = ultostr(decimal, 16);
NSString *hex = [NSString stringWithUTF8String:hexChar];
return hex;
}
/// 十六进制转换为二进制
+ (NSString *)getBinaryByHex:(NSString *)hex {
// 十进制
NSInteger decimal = [NSString getDecimalByHex:hex];
// 二进制字符串
NSString *binary = [NSString getBinaryByDecimal:decimal];
return binary;
}
/// 二进制转换成十六进制
+ (NSString *)getHexByBinary:(NSString *)binary {
// 十进制
NSInteger decimal = [NSString getDecimalByBinary:binary];
// 十六进制
NSString *hex = [NSString getHexByDecimal:decimal];
return hex;
}
@end
