Using Checks in C - Help!

hi,

friend of mine did coding for checks because i had to submit project yesterday but today when i was check how he did it i am unable to understand

also what is isdigit


here is the code:

Code:

int checkNumber(char [], int);
int checkLetters(char []);

----------------------

int checkNumber(char number[], int allowDots) {
    
    for (int i = 0; i < strlen(number); i++) {    
    
        if (!allowDots)
    
        if (!isdigit(number[i]))
    
        return 0;
    
    }
    
    return 1;

}

int checkLetters(char string[]) {
    
    for (int i = 0; i < strlen(string); i++) {    
          
           if (isdigit(string[i]))
          
              return 0;
    
    }
    
    return 1;

}

Do you understand how loops and if statements work?

If Statements in C - Cprogramming.com
For, While and Do While Loops in C - Cprogramming.com

isdigit?

isdigit - Google

deadplanet, yes i know how while and loop statement works.

Then use some sample input and go through it on pen and paper, writing down the new values of the variables at each line.

rather than ask 'what is 'isdigit' here' and hope for a reply, why not google isdigit and find the answer in about 5 seconds with no waiting