117，字符串的转换

#import <Foundation/Foundation.h>

int main(int argc,const
char * argv[]) {

NSString *str =
@"abc";

//1，将字符串转成大写

NSString *newStr1 = [str
uppercaseString];

NSLog(@"newStr1 = %@",newStr1);

//2，将字符串转成小写

NSString *newStr2 = [newStr1
lowercaseString];

NSLog(@"newStr2 = %@",newStr2);

//3，将字符串的首字母转成大写的

NSString *newStr3 = [str
capitalizedString];

NSLog(@"newStr3 = %@",newStr3);

//4，字符串转成基本数据类型

//注意，字符串里面不能包含其他非数字的字符，要不，转成后，只会截取数字部分直到遇见非数字为止，后面将被抛弃。eg：

//NSString *str1 = @"11a0"; [str1 intValue]结果为 11

//NSString *str1 = @"1b1a0"; [str1 intValue]结果为 1

NSString *str1 =
@"110";

NSString *str2 =
@"220";

int sum = [str1
intValue] +[str2 intValue];

NSLog(@"sum = %i",sum);

//5，OC字符串和C语言字符串的转换

NSString *str4 =@"I'm a super man!";

const char *str5 = [str4UTF8String];

NSLog(@"OC字符串转成C字符串：str5
= %s",str5);

const char *str6 ="ljs";

NSString *str7 = [NSStringstringWithUTF8String:str6];

NSLog(@"C字符串转成OC字符串:str7
= %@",str7);

//注：另外的一些方法

//1，求字符串的长度

NSString *str =
@"adbJS";

NSUInteger length = [str
length];

NSLog(@"length = %lu",length);

//2，取字符串某一个位置的字符

unichar c = [str
characterAtIndex:1];

NSLog(@"c = %c",c);

return 0;

}

//2015-12-20 12:00:25.971 12，字符串的转换[2250:186964] newStr1 = ABC

//2015-12-20 12:00:25.971 12，字符串的转换[2250:186964] newStr2 = abc

//2015-12-20 12:00:25.972 12，字符串的转换[2250:186964] newStr3 = Abc

//2015-12-20 12:00:25.972 12，字符串的转换[2250:186964] sum = 330

//2015-12-20 12:00:25.972 12，字符串的转换[2250:186964] OC字符串转成C字符串：str5
= I'm a super man!

//2015-12-20 12:00:25.972 12，字符串的转换[2250:186964] C字符串转成OC字符串:str7
= ljs

//2015-12-20 13:37:02.994 13，字符串的其他函数[2508:223160] length = 5

//2015-12-20 13:37:02.995 13，字符串的其他函数[2508:223160] c = d

//Program ended with exit code: 0