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Sidetrack: Reading Variable Values with scanf() and atoi()

Formatted input read from standard input (e.g. keyboard) 

scanf(format-string, expr1, expr2, …);

Converting string into integer 

int value = atoi(string);

Example: 

#include <stdio.h>   // includes definition of and scanf()
#include <stdlib.h>  // includes definition of atoi()

#define INPUT_STRLEN 20

...

char str[INPUT_STRLEN];
int n;

printf("Enter a string: ");
scanf("%19s", str);
n = atoi(str);
printf("You entered: \"%s\". This converts to integer %d.\n", str, n);


Enter a string: 9024
You entered: "9024". This converts to integer 9024.