Every Data Type in C — Size, Range & Precision

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

int main() {
    printf("%-12s size=%zu bytes   range: %d to %d\n",
           "char", sizeof(char), CHAR_MIN, CHAR_MAX);
    printf("%-12s size=%zu bytes   range: %d to %d\n",
           "short", sizeof(short), SHRT_MIN, SHRT_MAX);
    printf("%-12s size=%zu bytes   range: %d to %d\n",
           "int", sizeof(int), INT_MIN, INT_MAX);
    printf("%-12s size=%zu bytes   range: %ld to %ld\n",
           "long", sizeof(long), LONG_MIN, LONG_MAX);
    printf("%-12s size=%zu bytes   range: %lld to %lld\n",
           "long long", sizeof(long long), LLONG_MIN, LLONG_MAX);

    return 0;
}

#include <stdio.h>

int main() {
    signed char   s = -1;
    unsigned char u = -1;   // same bit pattern, different interpretation!

    printf("signed char with -1   = %d\n", s);
    printf("unsigned char with -1 = %d\n", u);   // wraps to the top of its range

    // The classic unsigned underflow bug
    unsigned int count = 0;
    count--;   // going below 0 wraps AROUND instead of going negative
    printf("unsigned int 0 - 1    = %u  (wrapped around!)\n", count);

    return 0;
}

#include <stdio.h>

int main() {
    float       f = 1.0 / 3.0;
    double      d = 1.0 / 3.0;
    long double ld = 1.0L / 3.0L;

    printf("float       (~7  digits): %.10f\n", f);
    printf("double      (~15 digits): %.10f\n", d);
    printf("long double (~18 digits): %.10Lf\n", ld);

    printf("\nsizeof(float)       = %zu bytes\n", sizeof(float));
    printf("sizeof(double)      = %zu bytes\n", sizeof(double));
    printf("sizeof(long double) = %zu bytes\n", sizeof(long double));

    return 0;
}

#include <stdio.h>

int main() {
    char letter = 'A';

    printf("'A' printed as %%c : %c\n", letter);
    printf("'A' printed as %%d : %d  (its ASCII code)\n", letter);

    // char arithmetic: adding a number shifts through the alphabet
    char next = letter + 1;
    printf("'A' + 1 = %c\n", next);

    // A string is just an array of these char boxes, ending in '\0'
    char word[] = "Hi";
    printf("\nword[0] = %c (code %d)\n", word[0], word[0]);
    printf("word[1] = %c (code %d)\n", word[1], word[1]);
    printf("word[2] = %d (the hidden null terminator)\n", word[2]);

    return 0;
}

#include <stdio.h>

int main() {
    // Implicit: int automatically becomes float during division
    int a = 7, b = 2;
    printf("7 / 2 (int/int)        = %d   (truncated, no cast)\n", a / b);
    printf("(float)7 / 2           = %.1f (explicit cast forces float math)\n", (float)a / b);

    // Explicit: forcing a float DOWN into an int truncates the decimal part
    float price = 9.99;
    int wholePart = (int)price;
    printf("(int)9.99              = %d   (decimal part simply dropped)\n", wholePart);

    // Overflow: forcing a big int into a small type wraps around
    int big = 300;
    char small = (char)big;   // char only holds up to 127
    printf("(char)300              = %d   (wrapped — 300 doesn't fit in a char)\n", small);

    return 0;
}