Difference between %d and %i format specifier in C language.

Format Specifiers

In C programming language, %d and %i are format specifiers as where %d specifies the type of variable as decimal and %i specifies the type as integer. In usage terms, there is no difference in printf() function output while printing a number using %d or %i but using scanf the difference occurs. scanf() function detects base using %i but assumes base 10 using %d.

Example (C)

 Live Demo

#include <stdio.h> int main() {    int num1 ,num2;    int num3, num4;    scanf("%i%d",&num1 , &num2);    printf("%i\t%d
",num1, num2);    num3 = 010;    num4 = 010;    printf("%i\t%d",num3, num4);    return 0; }

Output

32767-498932064 8 8

Here 010 is an octal number. scanf read the number as 10 using %d and read the number as 8 using %i. printf is good in both case to read the number as octal.