Question

4.16 LAB: Checker for integer string

Instructor note:

This zyLab counts as a homework grade and is due by 11:59pm on 9Oct.

Forms often allow a user to enter an integer. Write a program that takes in a string representing an integer as input, and outputs yes if every character is a digit 0-9. You may assume that the string does not contain spaces and will always contain less than 50 characters.

Ex: If the input is:

1995

the output is:

yes

Ex: If the input is:

42,000 

or

1995!

the output is:

no

Hint: Use a loop and the isdigit() function (don't forget to include the ctype library).

c progamming

Answer 1

#include<stdio.h>

int main(void)
{
   char userString[20];
   int isValid = 1, i;
   
   scanf("%s",userString);
  
   for(i = 0;userString[i]!='\0';i++){
      if(!(userString[i]>='0' && userString[i]<='9')){
         isValid = 0;
         break;
      }
   }
   
   if(isValid==1)
   {
      printf("yes\n");
   }
   else{
      printf("no\n");
   }

   return 0;
}