Input validation of an Integer using atoi()

Question

#include \"stdafx.h\"
#include 

void main()
{
    char buffer[20];
    int num;

    printf(\"Please enter a number\\n\");
    fgets(buffer, 20, std         


        

Answer 1

There is the isdigit function that can help you check each character:

#include 

/* ... */

for (i=0; buffer[i]; i++) {
        if (!isdigit(buffer[i])) {
            printf("Bad\n");
            break;
        }
}