Data Types

Introduction

Types tell the compiler how to interpret bits — integers, characters, and floating-point forms each have rules for size, range, and printf/scanf specifiers.

Understanding the topic

Integer types char, short, int, long — signed or unsigned.

Floating point float (single), double (double precision).

Format specifiers %d int, %c char, %f float, %lf double, %s string.

• Integer types — char, short, int, long — signed or unsigned.
• Floating point — float (single), double (double precision).
• Format specifiers — %d int, %c char, %f float, %lf double, %s string.

Step-by-step explanation

1. Integer types — char, short, int, long — signed or unsigned.
2. Floating point — float (single), double (double precision).
3. Format specifiers — %d int, %c char, %f float, %lf double, %s string.

Syntax reference

Syntax reference:

int | char | float | double | short | long

Informative example

Example program:

#include <stdio.h>

int main(void) {
    int i = 42;
    char c = 'X';
    float f = 3.14f;
    double d = 3.1415926535;
    printf("int:%d char:%c float:%f double:%lf\n", i, c, f, d);
    return 0;
}

int:42 char:X float:3.140000 double:3.141593

Execution workflow

Best practices

• Enable warnings: gcc -Wall -Wextra -std=c11 source.c -o app
• Give every variable a defined value before it is read.
• Stay inside array bounds — C will not stop you from over-running a buffer.

Common mistakes

• Reading uninitialized storage — behavior is undefined.
• Dismissing compiler warnings instead of fixing root causes.
• Ignoring NULL returns from malloc, fopen, and similar APIs.

Hands-on exercise

Practice problems:

• Print sizeof each type
• Use correct specifier for each variable

Summary

Data Types in C — Integer, character, and floating forms plus printf format codes.