How to use basic data types
Use integer types
char, short, int, long, and long long have implementation-defined ranges. Unsigned variants cannot represent negative values.
int count = 42;
long population = 1000000L;
unsigned int flags = 3U;Use floating types
float, double, and long double represent finite approximations. Prefer double for ordinary calculations.
double distance = 12.75;
printf("%.2f\n", distance);Measure with sizeof
sizeof returns a byte count as size_t. Do not assume that an int is always four bytes.
printf("int: %zu bytes\n", sizeof(int));
printf("double: %zu bytes\n", sizeof(double));Use fixed-width types when required
Include stdint.h when a file format or protocol requires an exact width. Use stdbool.h for the portable C17 spelling bool.
#include <stdbool.h>
#include <stdint.h>
bool ready = true;
uint32_t packet_id = UINT32_C(100);