[AwesomeProgrammer]

Hi. I am starting out on objective C and I made this program:

 #import <Foundation/Foundation.h>

int main(int argc, const char * argv[])
{
    BOOL myBool = TRUE;
    
    while (myBool == TRUE) {
        int a, b, sum;
        char ans;
        
        NSLog(@"Welcome to my calculator. Type in the first number: ");
        scanf("%d", &a);
        
        check.integer <- function(a){
            !length(grep("[^[:digit:]]", format(a, scientific = FALSE)))
        }
        
        check.integer(a)
        
        NSLog(@"Type in the second number: ");
        scanf("%d", &B)/>;
        
        sum = a + b;
        NSLog(@"The answer is: %d", sum);
        
        NSLog(@"Do you want to put in another sum? (y/n)");
        scanf("%s", &ans);
        
        if (ans=='y'){
            myBool = TRUE;
        }
        
        else if (ans=='n'){
            myBool = FALSE;
        }
        while (myBool==FALSE) {
            return 0;
        }

    }
    return 0;
}

It works perfectly fine, however, I would like to be able to compare the input and if the input isn't an integer display a message that says 'Please type in an integer.'
I looked this up on some websites but I couldn't find the thing I needed. Could someone help?

AwesomeProgrammer, on 14 February 2013 - 10:09 AM, said:

Hi. I am starting out on objective C and I made this program:

 #import <Foundation/Foundation.h>

int main(int argc, const char * argv[])
{
    BOOL myBool = TRUE;
    
    while (myBool == TRUE) {
        int a, b, sum;
        char ans;
        
        NSLog(@"Welcome to my calculator. Type in the first number: ");
        scanf("%d", &a);
        
        NSLog(@"Type in the second number: ");
        scanf("%d", &B)/>/>;
        
        sum = a + b;
        NSLog(@"The answer is: %d", sum);
        
        NSLog(@"Do you want to put in another sum? (y/n)");
        scanf("%s", &ans);
        
        if (ans=='y'){
            myBool = TRUE;
        }
        
        else if (ans=='n'){
            myBool = FALSE;
        }
        while (myBool==FALSE) {
            return 0;
        }

    }
    return 0;
}

It works perfectly fine, however, I would like to be able to compare the input and if the input isn't an integer display a message that says 'Please type in an integer.'
I looked this up on some websites but I couldn't find the thing I needed. Could someone help?