Data Types in C++ — Revision Notes

Definition

Syntax

int wholeNumber;
double decimalNumber;
char singleCharacter;
bool trueOrFalse;

Example

#include <iostream>
using namespace std;

int main() {
    int age = 20;
    double gpa = 8.9;
    bool isEnrolled = true;
    cout << age << " " << gpa << " " << isEnrolled << endl;
    return 0;
}

Output

Important Points

• bool stores only true or false.
• double is generally preferred over float for precision.
• auto combined with type suffixes (like 5.0f for float) controls exactly what type is inferred.
• Use std::string (from <string>) for real text, not just char.

Common Mistakes

• Confusing C++'s std::string with C's raw char arrays.
• Forgetting that bool prints as 1/0 unless you use boolalpha.
• Losing precision by assigning a double into a float.

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