C Programming: Visual Quickstart Guide

Reading Numeric Input

The previous two examples read in a single character and then an entire string. But what if you want to read in numeric input? For this, you can again use the scanf() function:

int age;
printf ("Enter your age: ");
scanf ("%d", &age);

This method generally works and has the added benefit of familiarity. Unfortunately, this function can be unreliable in properly handling numeric input (although it's still commonly used). A better solution—which is really a kludge (an inelegant solution)—uses the fgets() and sscanf() functions:

int age;
char input[10];
printf ("Enter your age: ");
fgets (input, sizeof(input)-1, stdin);
sscanf (input, "%d", &age)

With the fgets() function, the first argument (input) tells C to which variable ...