Validating string for integers

[mlsbbe]

I want to validate the string below for integers, and if there is a letter, I want the program to exit.

>>name,1,2,3,4

if the string is something like this

>>name,1,23,34,2a

I want the program to exit.

Does anybody know where to start? What functions should I use? Just point me in the general direction.

Thanks.

[Vber]

Hmm, try building a function by yourself, the function runs in the string and check every char to see if one of them is character (ascii value of a char) if yes, return false and this will stop the program...

A little example can be found here, I did it in 2 minutes so don't look at the code

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

int existCh (char *str) {
	while (*(str++))
		if (isalpha(*str)) //if its alphabetic
			return 1; //return true, yes, exist a char
	
	return 0; //return false, don't exit a char
}

int main(void) {
	char *test = "14s43";

	if (existCh(test))
		printf("Hello, in the string: %s, there is a alphabetic char!\n",test);
	else
		printf("Lucky, in the string: %s, there isn't any alphabetic char\n",test);

	return 0;
}

[Brighteyes]

I find that the str* functions are handy for stuff like this, just set up a string of bad characters to look for and use something like strpbrk to search for them

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

static void die(char *msg);

int main(void)
{
    int rc;
    char *p;
    char buf[1001];
    /* Use whatever letters you want based on locale and testing needs */
    char *inval = "abcdefghijklmnopqrstuvwxyz";

    printf("Enter a string: ");
    fflush(stdout);

    /* Get the line */
    rc = scanf("%1000[^\n]", buf);
    if (rc == EOF)
        die("End of file reached...");
    else if (rc < 1)
        die("I/O error detected...");
    else
    {
        scanf("%*[^\n]"); /* Get rid of extraneous input */
        getchar();
    }

    /* Check it */
    p = strpbrk(buf, inval);
    if (p != NULL)
        fprintf(stderr, "Invalid number detected >%c<\n", *p);
    else
        printf("%s\n", buf);

    return EXIT_SUCCESS;
}

static void die(char *msg)
{
    fprintf(stderr, "Fatal error: %s\n", msg);
    exit(EXIT_FAILURE);
}

[Hammer]

while (*(str++))
  if (isalpha(*str)) //if its alphabetic
    return 1; //return true, yes, exist a char

A minor problem, incrementing str within the while statement causes it to be incremented before the first character in the array gets checked, so you could end up with this:

Lucky, in the string: a1443, there isn't any alphabetic char

There are some validation examples in the FAQ . Also, some number reading examples.

[Vber]

correct sir thanks.