基本数据类型转换成字符串

// 1.int -> NSString
int i = 10;
NSString *str = [NSString stringWithFormat:@"%d",i];
NSLog(@"%@",str);

// 2.double ->NSString
double d = 4.5673;
NSString *str1 = [NSString stringWithFormat:@"%.4f",d];
NSLog(@"%@",str1);

// 3.float ->NSString
float f = 4.5;
NSString *str2 = [NSString stringWithFormat:@"%.1f",f];
NSLog(@"%@",str2);

// 4.char ->NSString
char c = 'b';
NSString *str3 = [NSString stringWithFormat:@"%c",c];
NSLog(@"%@",str3);

// 5.NSString ->int
NSString *str4 = @"143";
int i1 = [str4 intValue];
NSLog(@"%d",i1);

// 6.NSString ->double
NSString *str5 = @"45.4567";
double d1 = [str5 doubleValue];
NSLog(@"%.4f",d1);

// 7.NSString ->float
NSString *str6 = @"23.2";
float f1 = [str6 floatValue];
NSLog(@"%.1f",f1);

// 8.将字符串中得字母大写
NSString *str7 = @"china";
NSString *str8 = [str7 uppercaseString];
NSLog(@"%@",str8);

// 9.将字符串中得字母小写
NSString *str9 = @"CHINA";
NSString *str10 = [str9 lowercaseString];
NSLog(@"%@",str10);

// 10.将字符串的首字母大写
NSString *str11 = @"china";
NSString *str12 = [str11 capitalizedString];
NSLog(@"%@",str12);