Object-c一些基础知识

int main(int argc,const char *argv[])
{
return 0;
}

0代表程序是正常退出，任何非0的返回值代表有错误产生

NSLog输出各种数据类型的表达式

#import <Foundation/Foundation.h>

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

@autoreleasepool {

char a       = 'a';
short int  sint  = 12;
unsigned short int usint = 22;
int intVar = 32;
unsigned int uintVar = 42;
long int lintVar = 52;
unsigned long int ulongIntVar= 62;
long long int llintVar = 500ll;
unsigned long long int ullintVar = 12ull;
float floatVar = 12.34f;
double  doubleVar = 12.34;
long double ldoubleVar = 12.34L;
id idVar = nil;
NSString *name = @"test";
BOOL isTrue = YES;

NSLog(@"bool = %i",isTrue);//布尔值
NSLog(@"String = %@",name);//字符串
        NSLog(@"charVar = %c",a);//字符
NSLog(@"shortIntVar: hi:%hi,hx:%hx,ho:%ho",sint,sint,sint);//十进制，十六进制，八进制short int
NSLog(@"unsignedShortIntVar: hu:%hu,hx:%hx,ho:%ho",usint,usint,usint);//十进制，十六进制，八进制unsigned short int
NSLog(@"intValue:i:%i,x:%x,o:%o",intVar,intVar,intVar);//十进制，十六进制，八进制int
NSLog(@"unsigned int Value:u:%u,x:%x,o:%o",uintVar,uintVar,uintVar);//十进制，十六进制，八进制unsigned int
NSLog(@"long int:li:%li,lx:%lx,lo:%lo",lintVar,lintVar,lintVar);//十进制，十六进制，八进制long int
NSLog(@"unsigned long int:lu:%lu,lx:%lx,lo:%lo",ulongIntVar,ulongIntVar,ulongIntVar);//十进制，十六进制，八进制unsigned long int
NSLog(@"long long int:lli:%lli,llx:%llx,llo:%llo",llintVar,llintVar,llintVar);//十进制，十六进制，八进制unsigned long long int
NSLog(@"unsigned long long int:llu:%llu,llx:%llx,llo:%llo",ullintVar,ullintVar,ullintVar);//十进制，十六进制，八进制unsigned long long int
NSLog(@"float:f:%f,e:%e,g:%g,a:%a",floatVar,floatVar,floatVar,floatVar);//float
NSLog(@"double:f:%f,e:%e,g:%g,a:%a",doubleVar,doubleVar,doubleVar,doubleVar);//double
NSLog(@"long double:Lf:%Lf,Le:%Le,Lg:%Lg",ldoubleVar,ldoubleVar,ldoubleVar);//long double
NSLog(@"id:p=%p",idVar);//id

}
return 0;
}

键盘输入的示例

#import <Foundation/Foundation.h>

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

@autoreleasepool {

int n,number,triangularNumber;

NSLog(@"What triangular number do you want?");
scanf("%i",&number);

triangularNumber = 0;
for (n  = 1; n<= number; ++n)
{
triangularNumber += n;
}

NSLog(@"Triangular number %i is %i\n",number,triangularNumber);
}
return 0;
}

对象用.符号获得属性，相当于调用其的setter和getter方法

instance.property = value 相当于[instance setProperty:value]