//선언 부분
#import <Foundation/Foundation.h>

@interface cal : NSObject
{
        double input_1;
        double input_2;
        double temp;
}
-(void) scan; // 입력
-(void) addition; //덧셈
-(void) subtraction; // 뺄셈
-(void) multiplication; // 곱셈
-(void) division; // 나눗셈

@end


//실행 부분
#import "cal.h"


@implementation cal
-(void) scan
{
        scanf("%lf %lf", &input_1, &input_2);
}

-(void) addition
{
        temp = input_1 + input_2;
        NSLog(@"%the result is %lf", temp);
}

-(void) subtraction
{
        temp = input_1 - input_2;
        NSLog(@"%the result is %lf", temp);
}

-(void) multiplication
{
        temp = input_1 * input_2;
        NSLog(@"%the result is %lf", temp);
}

-(void) division
{
        temp = input_1 / input_2;
        NSLog(@"%the result is %lf", temp);
}

@end


//메인 부분
#import "cal.h"

int main (int argc, const char * argv[]) {
    NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
        cal *mycal = [[cal alloc] init];
        
        char calculation;
        
        NSLog(@"연산자를 입력하세요.('+', '-', '*', '/'중 택1");
        scanf("%c", &calculation);
        
        NSLog(@"연산할 두 수를 입력하세요.");
        [mycal scan];
        
                if( calculation == '+')
                {
                        [mycal addition];
                }
                else if( calculation == '-')
                {
                        [mycal subtraction];
                }
                else if( calculation == '*')
                {
                        [mycal multiplication];
                }
                else if( calculation =='/')
                {
                        [mycal division];
                }
                else
                {
                        NSLog(@"잘못 입력 하셨습니다.");
                }
        
        [mycal release];
    [pool drain];
    return 0;
}


이렇게 소스를 짰는데 값이 이상하게 나와버려서 질문드립니다.

Objective - C입니다.
이 게시물을...