C++ Standard Library Function
- The C++ Standard Library offers a rich set of functions for common mathematical calculations, string manipulations, character manipulations, input / output, error checking and many other useful operations to perform.
- It makes it easier for the programmer to operate, because these functions provide many of the programmers ' skills required.
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| Library Function in C++ |
- The functions of the C++ Standard Library are supported as part of the C++ programming environment.
- Header file names ending in .h are "old-style" header files that have been superseded by the C++ Standard Library header files.
C++ Standard Library header file
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Explanation
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<iostream>
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Contains function prototypes for the C++ standard input and standard output functions. This header file replaces header file <iostream.h>.
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<iomanip>
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Contains function prototypes for stream manipulators that format streams of data. This header file replaces header file <iomanip.h>.
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<cmath>
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Contains function prototypes for math library functions. This header file replaces header file <math.h>.
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<cstdlib>
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Contains function prototypes for conversions of numbers to text, text to numbers, memory allocation, random numbers and various other utility functions. This header file replaces header file <stdlib.h>.
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<ctime>
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Contains function prototypes and types for manipulating the time and date. This header file replaces header file <time.h>.
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<cctype>
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Contains function prototypes for functions that test characters for certain properties (such as whether the character is a digit or a punctuation), and function prototypes for functions that can be used to convert lowercase letters to uppercase letters and vice versa. This header file replaces header file <ctype.h>
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<cstring>
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Contains function prototypes for C-style string-processing functions. This header file replaces header file <string.h>.
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<cstdio>
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Contains function prototypes for the C-style standard input/output library functions and information used by them. This header file replaces header file <stdio.h>.
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<fstream>
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Contains function prototypes for functions that perform input from files on disk and output to files on disk. This header file replaces header file <fstream.h>.
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<climits>
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Contains the integral size limits of the system. This header file replaces header file <limits.h>.
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<cassert>
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Contains macros for adding diagnostics that aid program debugging. This replaces header file <assert.h> from pre-standard C++.
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<cfloat>
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Contains the floating-point size limits of the system. This header file replaces header file <float.h>.
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<string>
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Contains the definition of class string from the C++ Standard Library
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<vector>,
<list>, <deque>, <queue>, <stack>, <map>, <set>, <bitset> |
These header files contain classes that implement the C++ Standard Library containers. Containers store data during a program's execution.
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<typeinfo>
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Contains classes for runtime type identification (determining data types at execution time).
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<exception>,
<stdexcept> |
These header files contain classes that are used for exception handling.
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<memory>
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Contains classes and functions used by the C++ Standard Library to allocate memory to the C++ Standard Library containers.
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<sstream>
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Contains function prototypes for functions that perform input from strings in memory and output to strings in memory.
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<functional>
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Contains classes and functions used by C++ Standard Library algorithms.
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<iterator>
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Contains classes for accessing data in the C++ Standard Library containers.
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<algorithm>
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Contains functions for manipulating data in C++ Standard Library containers.
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<locale>
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Contains classes and functions normally used by stream processing to process data in the natural form for different languages (e.g., monetary formats, sorting strings, character presentation, etc.).
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<limits>
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Contains classes for defining the numerical data type limits on each computer platform.
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<utility>
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Contains classes and functions that are used by many C++ Standard Library header files.
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Mathematical Functions
Some of the important mathematical functions in header file <cmath> are
| Function | Meaning |
| sin(x) | Sine of an angle x (measured in radians) |
| cos(x) | Cosine of an angle x (measured in radians) |
| tan(x) | Tangent of an angle x (measured in radians) |
| asin(x) | Sin-1 (x) where x (measured in radians) |
| acos(x) | Cos-1 (x) where x (measured in radians) |
| exp(x) | Exponential function of x (ex) |
| log(x) | logarithm of x |
| log 10(x) | Logarithm of number x to the base 10 |
| sqrt(x) | Square root of x |
| pow(x, y) | x raised to the power y |
| abs(x) | Absolute value of integer number x |
| fabs(x) | Absolute value of real number x |
Character Functions
- All the character functions require <cctype> header file. The following table lists the function.
| Function | Meaning |
| isalpha(c) | It returns True if C is an uppercase letter and False if c is lowercase. |
| isdigit(c) | It returns True if c is a digit (0 through 9) otherwise False. |
| isalnum(c) | It returns True if c is a digit from 0 through 9 or an alphabetic character (either uppercase or lowercase) otherwise False. |
| islower(c) | It returns True if C is a lowercase letter otherwise False. |
| isupper(c) | It returns True if C is an uppercase letter otherwise False. |
| toupper(c) | It converts c to uppercase letter. |
| tolower(c) | It converts c to lowercase letter. |