Format Specifiers in C

Format specifiers define the type of data to be printed on standard output. You need to use format specifiers whether you're printing formatted output with printf() or accepting input with scanf().

Some of the % specifiers that you can use in ANSI C are as follows:

Examples:

%c single character format specifier:

#include <stdio.h> 

int main() { 
  char first_ch = 'f'; 
  printf("%c\n", first_ch); 
  return 0; 
}

Output:

f

%s string format specifier:

#include <stdio.h> 

int main() { 
  char str[] = "freeCodeCamp"; 
  printf("%s\n", str); 
  return 0; 
}

Output:

freeCodeCamp

Character input with the %c format specifier:

#include <stdio.h> 

int main() { 
  char user_ch; 
  scanf("%c", &user_ch); // user inputs Y
  printf("%c\n", user_ch); 
  return 0; 
}

Output:

Y

String input with the %s format specifier:

#include <stdio.h> 

int main() { 
  char user_str[20]; 
  scanf("%s", user_str); // user inputs fCC
  printf("%s\n", user_str); 
  return 0; 
}

Output:

fCC

%d and %i decimal integer format specifiers:

#include <stdio.h> 

int main() { 
  int found = 2015, curr = 2020; 
  printf("%d\n", found); 
  printf("%i\n", curr); 
  return 0; 
}

Output:

2015
2020

%f and %e floating point number format specifiers:

#include <stdio.h>

int main() { 
  float num = 19.99; 
  printf("%f\n", num); 
  printf("%e\n", num); 
  return 0; 
}

Output:

19.990000
1.999000e+01

%o octal integer format specifier:

#include <stdio.h> 

int main() { 
  int num = 31; 
  printf("%o\n", num); 
  return 0; 
}

Output:

37

%x hexadecimal integer format specifier:

#include <stdio.h> 

int main() { 
  int c = 28; 
  printf("%x\n", c); 
  return 0; 
}

Output:

1c