[Solved] Repeating an Input till it is answered Correct

Question

The computer must repeat the question till it recieves a valid response.

It (output) goes like this indefinitely.

Reason :

The problem is that you are receiving input only once in your code and then entering into loop to check for the age.

since age value is not re-assigned after every iteration, if the first intput is !=32767 it’s always wrong and enters into an infinite loop or also known as the odd loop.

scanf("%d", &age); //scans only once

do //enters loop
{
    if (age == 32767)
    {
        printf("Error, retry: \n");
    }

    else
    {
        printf("Cool.");
    }
} while(age!=32767);

The if else statement is to catch the exception incase the user types something that is not an integer.

No, if (age == 32767) would only check if the entered response was equal to 32767 or not.
From @davmac ‘s comment , you can never check for an input value greater than the maximum value of the int variable.
Instead it’d be better if you would assign a range this way
```
 `if (age > 100 || age <0 )`
```

Solution :

to avoid this scan age for every iteration and also see the changes I’ve done :

do{

    printf("How old are you?\n");

    if(scanf("%d", &age)==1) //checking if scanf is successful or not
    {

        if (age > 100 || age <0 )
        {
            printf("Error, retry: \n");
        }

        else
        {
            printf("Cool.");
            break; //break loop when correct value is entered
        }
    }

    else //if scanf is unsuccessful 
    {
        char c;
        printf("enter only integers\n");

        do
        {
            scanf("%c",&c);
        }while( c !='\n' && c!= EOF ); //consuming characters
    }

}while(1); //always true

Accepted Answer