kameshkotwani / cpp-cheat-sheet

A simple README file that contains valuable information about C++ data types, their max-values, common-functions, and much more.

C++ Reference Cheat-Sheet

Common Data Types

data type	bits	Range
int	32-bits	-2,147,483,647 to 2,147,483,647
INT_MAX	32-bits	2,147,483,647 (constant)
INT_MIN	32-bits	-2,147,483,647 (constant)
char	8-bits, 1-byte	-127 to 127

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Useful Tips

1. To check for Integer overflow

• we have to define #define INT_MIN (-INT_MAX-1) due to this Stack-Overflow-Boolean-Issue.
• check if the result is getting overflow using this parameter if(result>INT_MAX/10 || result<INT_MIN/10) return false or return 0.

2. To check how much time the execution took place:

• Add this code snippet at the end of main function: cerr<<"time taken : "<<(float)clock()/CLOCKS_PER_SEC<<" secs"<<"\n";

3. To watch any variable while debugging

• #define watch(x) cout << (#x) << " is " << (x) << "\n"

4. To calculate GCD use built-in function

• __gcd(x,y); there are two underscores _ _ not one

5. make cin and cout faster

• `ios::sync_with_stdio(false); you cannot use printf and scanf

6. Incredible use of auto

• auto i=10; will automatically assign int.
• auto k=20LL; will automatically assign long long
• auto z=1.0; will automatically assign double
• auto s="somestring;" will automatically assign string

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Bit Magic Techniques

1.

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Math Functions

Function	Description
double cos(double)	Takes an angle (as a double) and returns the cosine.
double sin(double)	Takes an angle (as a double) and returns the sine.
double tan(double)	Takes an angle (as a double) and returns the tangent.
double log(double)	Takes a number and returns the natural log (base-e) of that number.
double pow(double)	The first is a number you wish to raise and the second is the power youwish to raise it to.
double sqrt(double)	Returns square-root of the number.
int abs(int)	Returns the absolute value.
double fabs(double)	Returns the absolute value of any decimal number. (eg, 1,1.56,-3.99).
double floor(double)	Returns the number less than or equal to the number passed.

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STL Containers and Functions

Under Construction.