Question

Without using isdigit, create a C function that scans in a string, checks if its an int, and returns the int. If the string is an integer, the function should return the int otherwise return “not a number.” i.e. if user enters “5", the function returns 5, but if the user enters “hi” the function will return “not a number."

Answer 1

#include <stdio.h>
#include <string.h>
char* fun(char* c){
int i=0;
for(i=0;i<strlen(c);i++)
{
if(c[i]<'0' || c[i]>'9')
return "Not a number";
}
return c;
}

int main()
{
  
char c[50];
printf("Enter the string: ");
scanf("%s",c);
printf("%s",fun(c));
  

return 0;
}