String Functions

`Function Declaration`	`Description`	`Header File`
`int atoi(const chara[]);`	`Converts a string of characters to an integer.`	`cstdlib`
`int stoi(const string)`	`Converts a STL string object to an integer. C++11 and higher.`	`string`
`long atol(const chara[]);`	`Converts a string of characters to a long integer.`	`cstdlib`
`long stol(const string)`	`Converts a STL string object to a long. C++11 and higher.`	`string`
`double atof(const char a[]);`	`Converts a string of characters to a double.`	`cstdlib`1
`strcat(String_Variable, String_Expression);`	`Appends the value of the String_Expression to the end of the string in the String_Variable.`	`cstring`
`strcmp(String_Exp1, String_Exp2)`	`Returns true if the values of the two string expressions are different; otherwise, returns false.2`	`cstring`
`strcpy(String_Variable, String_Expression);`	`Changes the value of the String_Variable to the value of the String_Expression.`	`cstring`
`strlen(String_Expression)`	`Returns the length of the String_Expression.`	`cstring`
`strncat(String_Variable, String_Expression, Limit);`	`Same as strcat except that at most Limit characters are appended.`	`cstring`
`strncmp(String_Exp1, String_Exp2, Limit)`	`Same as strcmp except that at most Limit characters are compared.`	`cstring`
`strncpy(String_Variable, String_Expression, Limit);`	`Same as strcpy except that at most Limit characters are copied.`	`cstring`
`strstr(String_Expression, Pattern)`	`Returns a pointer to the first occurrence of the string Pattern in String_Expression. Returns the NULL pointer if the Pattern is not found.`	`cstring`
`strchr(String_Expression, Character)`	`Returns a pointer to the first occurrence of the Character in String_Expression. Returns the NULL pointer if Character is not found.`	`cstring`
`strrchr(String_Expression, Character)`	`Returns a pointer to the last occurrence of the Character in String_Expression. Returns the NULL pointer if Character is not found.`	`cstring`
¹ Some implementations place it in `cmath`. ² Returns an integer that is less than zero, zero, or greater than zero according to whether String_Exp1 is less than, equal to, or greater than String_Exp2, respectively. The ordering is lexicographic ordering.