I'm trying to do a simple C program and I need to figure out how to check if a user input is an integer?

I'm doing a simple program that calculates sales tax to a purchase and displays the tax amount and the total cost. I'm using C (NOT C++) and the user will input the sale price then I am to convert that into the total sale and what the tax would be. Now I need to check the input that the user gives the program to verify that it is either a floating point or an integer. I think i need a float if they can use decimals right? Any help would be beneficial. Thank You For Your Time And Patience!!!

I'm trying to do a simple C program and I need to figure out how to check if a user input is an integer?
You can get sscanf to do much of the work for you. See below for some code I wrote to illustrate:





#include %26lt;stdio.h%26gt;


#include %26lt;stdlib.h%26gt;


#include %26lt;string.h%26gt;





#define MAX_STR_LEN 256





typedef enum { NONE = 0, INT, FLOAT, STRING, OTHER } DATA_TYPE;





typedef struct {


DATA_TYPE type;


union {


long i;


double f;


char s[MAX_STR_LEN];


} data;


} input_t;





int main(int argc, char *argv[])


{


char *s = argv[1];


input_t in = { NONE, { 0 } };





if (argc != 2) {


printf("\nusage: %s %26lt;n%26gt;\n",argv[0]);


exit(EXIT_FAILURE);


}


if ((strchr(s,'.') != NULL) %26amp;%26amp; (sscanf(s,"%lf",%26amp;in.data.f) == 1)) {


in.type = FLOAT;


} else if (sscanf(s,"%ld",%26amp;in.data.i) == 1) {


in.type = INT;


} else if (sscanf(s,"%s",in.data.s) == 1) {


in.type = STRING;


memcpy(in.data.s,s,sizeof(MAX_STR_LEN));


} else {


in.type = OTHER;


}





switch (in.type) {


case (INT):


printf("\nInt : %ld\n",in.data.i);


break;


case (FLOAT):


printf("\nFlt : %g\n",in.data.f);


break;


case (STRING):


printf("\nStr : %s\n",in.data.s);


break;


default:


puts("\nInvalid input");


break;


}


exit(EXIT_SUCCESS);


}
Reply:You can use float.


Float can handle int but Int cannot handle float or decimals.
Reply:well it is very simple just use float or decimal if use type only integer value then there is no such problem and you should display as it is.