The C Library limits.h header file defines various properties of the different variable types. The macros defined in this header, limits the values of various variable types like char, int and long.

These limits specify that a variable cannot store any value beyond these limits, for example an unsigned character can store up to a maximum value of 255.

<limits.h> Library Macros

The following values are implementation-specific and defined using the #define directive. However, these values may not be lower than the given ones.

Note that, the above macros help developer to write efficient code that works consistently across different platforms and compilers.

Example 1

Following is the basic C Library program to display the range value of various macros under the limits.h header file.

#include <stdio.h>
#include <limits.h>

int main() {
   printf("The value of CHAR_BIT: %dn", CHAR_BIT);
   printf("The value of SCHAR_MIN: %dn", SCHAR_MIN);
   printf("The value of SCHAR_MAX: %dn", SCHAR_MAX);
   printf("The value of UCHAR_MAX: %un", UCHAR_MAX);
   printf("The value of CHAR_MIN: %dn", CHAR_MIN);
   printf("The value of CHAR_MAX: %dn", CHAR_MAX);
   printf("The value of MB_LEN_MAX: %dn", MB_LEN_MAX);
   printf("The value of SHRT_MIN: %dn", SHRT_MIN);
   printf("The value of SHRT_MAX: %dn", SHRT_MAX);
   printf("The value of USHRT_MAX: %un", USHRT_MAX);
   printf("The value of INT_MIN: %dn", INT_MIN);
   printf("The value of INT_MAX: %dn", INT_MAX);
   printf("The value of UINT_MAX: %un", UINT_MAX);
   printf("The value of LONG_MIN: %ldn", LONG_MIN);
   printf("The value of LONG_MAX: %ldn", LONG_MAX);
   printf("The value of ULONG_MAX: %lun", ULONG_MAX);
   return 0;
}

Output

On execution of above code, we get the following result −

The value of CHAR_BIT: 8
The value of SCHAR_MIN: -128
The value of SCHAR_MAX: 127
The value of UCHAR_MAX: 255
The value of CHAR_MIN: -128
The value of CHAR_MAX: 127
The value of MB_LEN_MAX: 16
The value of SHRT_MIN: -32768
The value of SHRT_MAX: 32767
The value of USHRT_MAX: 65535
The value of INT_MIN: -2147483648
The value of INT_MAX: 2147483647
The value of UINT_MAX: 4294967295
The value of LONG_MIN: -9223372036854775808
The value of LONG_MAX: 9223372036854775807
The value of ULONG_MAX: 18446744073709551615

Example 2

In this example, we illustrate the program for finding the minimum and maximum values.

#include <stdio.h>
#include <limits.h>

int main() {
   int input[] = {89, 5, 21, 10, 45, 31, 98};
   int n = sizeof(input) / sizeof(input[0]);

   // Initialization of macros
   int min_value = INT_MAX;
   int max_value = INT_MIN;
   
   // loop iteration for min and max value
   for (int i = 0; i < n; ++i) {
       if (input[i] < min_value) {
           min_value = input[i];
       }
       if (input[i] > max_value) {
           max_value = input[i];
       }
   }
   // Display the result
   printf("Minimum value: %dn", min_value);
   printf("Maximum value: %dn", max_value);

   return 0;
}

Output

On execution of above code, we get the following result −

Minimum value: 5
Maximum value: 98

Example 3

Below the program initializes limit macros(CHAR_MIN/MAX) to generate the minimum and maximum length of character from the given string.

#include <stdio.h>
#include <limits.h>
#include <string.h>

int main() {
   char* char_input[] = {"RUSSIA", "UK", "INDIA", "NEWYORK", "INDONESIA", "DUBAI"};
   int num_strings = sizeof(char_input) / sizeof(char_input[0]);

   // Initialization of CHAR macros
   int min_length = CHAR_MAX;
   int max_length = CHAR_MIN;

   for (int i = 0; i < num_strings; ++i) {
       int current_length = strlen(char_input[i]);
       if (current_length < min_length) {
           min_length = current_length;
       }
       if (current_length > max_length) {
           max_length = current_length;
       }
   }

   printf("Minimum length of characters: %dn", min_length);
   printf("Maximum length of characters: %dn", max_length);

   return 0;
}

Output

The above code produces the following result −

Minimum length of characters: 2
Maximum length of characters: 9