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// C integer constants
// Source: https://en.cppreference.com/w/c/language/integer_constant
#include <inttypes.h>
#include <stdio.h>
int main(void)
{
printf("123 = %d\n", 123);
printf("0123 = %d\n", 0123);
printf("0x123 = %d\n", 0x123);
printf("12345678901234567890ull = %llu\n", 12345678901234567890ull);
// the type is a 64-bit type (unsigned long long or possibly unsigned long)
// even without a long suffix
printf("12345678901234567890u = %"PRIu64"\n", 12345678901234567890u );
// printf("%lld\n", -9223372036854775808); // Error:
// the value 9223372036854775808 cannot fit in signed long long, which
// is the biggest type allowed for unsuffixed decimal integer constant
printf("%llu\n", -9223372036854775808ull );
// unary minus applied to unsigned value subtracts it from 2^64,
// this gives unsigned 9223372036854775808
printf("%lld\n", -9223372036854775807ll - 1);
// correct way to form signed value -9223372036854775808
}
// The following variables are initialized to the same value:
int d = 42;
int o = 052;
int x = 0x2a;
int X = 0X2A;
int b = 0b101010; // C23
// The following variables are also initialized to the same value:
unsigned long long l1 = 18446744073709550592ull; // C99
unsigned long long l2 = 18'446'744'073'709'550'592llu; // C23
unsigned long long l3 = 1844'6744'0737'0955'0592uLL; // C23
unsigned long long l4 = 184467'440737'0'95505'92LLU; // C23
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