Objective-C Foundation框架实践——NSString（二）

#import <Foundation/Foundation.h>

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

char *str1 = "Hello";
NSString *str2 = @"World";

//OC -> C
NSLog(@"OC->C = %s",[str2 UTF8String]);

//C -> OC
NSString *s = [NSString stringWithUTF8String:str1];
NSLog(@"C->OC = %@",s);

//这个是不需要我们去释放内存的；
NSString *str3 = @"iOS";

//这个需要我们去释放内存；只要是我们进行inti的；
NSString *str4 = [[NSString alloc]init];
str4 = @"OC";

//格式化字符串；
int a = 10;
NSString *str5 = [[NSString alloc] initWithFormat:@"%d",a];
NSLog(@"str5 = %@",str5);

//拼接字符串
NSString *str6 = [str3 stringByAppendingString:str4];
NSLog(@"str6 = %@",str6);

//大小写转换
//大写-->小写:不管原来的字符的大小写，一律转换为小写；
NSString *str7 = [str4 lowercaseString];
NSLog(@"Lower str4 = %@",str7);

//小写-->大写
NSString *str8 = [str7 uppercaseString];
NSLog(@"Upper str7 = %@",str8);

//前后缀的判断
NSString *str9 = @"ABCDEFG";

//这里Bool值的输出使用格式化%hhd，true输出1，false输出0；
BOOL hasPrefix = [str9 hasPrefix:@"ABC"];
NSLog(@"hasPrefix = %hhd",hasPrefix);

BOOL hasSuffix = [str9 hasSuffix:@"F6"];
NSLog(@"hasSuffix = %hhd",hasSuffix);

}
return 0;
}