i tried to run this code,

#include <cs50.h>
#include <stdio.h>
#include <ctype.h>

int main()
    int iRandom = 0;
    int iResponse = 0;

    iRandom = (rand() % 10) + 1;

    printf("\nGuess a number between 1 and 10: \n");
    scanf("%d", &iResponse);

        if isdigit(iResponse)

        printf("You did not enter a digit!\n");

        if(iResponse == iRandom)
        printf("\nYou guessed right\n");

        printf("You guessed wrong\n");
        printf("\nThe correct guess was %d\n", iRandom);


but the isdigit() function keeps processing it wrong even though my input was a digit;

/home/ubuntu/workspace/fooling/ $ ./guess

Guess a number between 1 and 10: 
You did not enter a digit!
You guessed wrong

The correct guess was 4

can you tell me what i did wrong?

1 Answer 1

  1. You are missing a pair of parentheses around this if statement

    if isdigit(iResponse)
  2. You are using isdigit() wrong. Its definition is

    int isdigit( int ch );

    Checks if the given character is a numeric character (0123456789). The behavior is undefined if the value of ch is not representable as unsigned char and is not equal to EOF.

    ch - character to classify

    Return value
    Non-zero value if the character is a numeric character, zero otherwise.

So you have to pass to it a char and it will tell you if it's a digit, not an int. The int in the definition's parameters, is because all chars can be represented as integers in C.

  1. You also have some stray curly braces.

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