Hi, i am trying to convert a simple integer or byte or anything else to a string in order to write to a file on disk. It does not work the way i did it for years with e.g. Microsoft C7.0 (Win3.1) and Visual C 6.0 (W32) - dont know why.
C++ provides following two types of string representations −
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The C-Style Character String
The C-style character string originated within the C language and continues to be supported within C++. This string is actually a one-dimensional array of characters which is terminated by a null character '0'. Thus a null-terminated string contains the characters that comprise the string followed by a null.
The following declaration and initialization create a string consisting of the word 'Hello'. To hold the null character at the end of the array, the size of the character array containing the string is one more than the number of characters in the word 'Hello.'
If you follow the rule of array initialization, then you can write the above statement as follows −
Following is the memory presentation of above defined string in C/C++ −
Actually, you do not place the null character at the end of a string constant. The C++ compiler automatically places the '0' at the end of the string when it initializes the array. Let us try to print above-mentioned string −
When the above code is compiled and executed, it produces the following result −
Fm8 sounds. C++ supports a wide range of functions that manipulate null-terminated strings −
Following example makes use of few of the above-mentioned functions −
When the above code is compiled and executed, it produces result something as follows −
The String Class in C++
The standard C++ library provides a string class type that supports all the operations mentioned above, additionally much more functionality. Let us check the following example −
When the above code is compiled and executed, it produces result something as follows −
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Controls conditional branching. Statements in the if-block are executed only if the if-expression evaluates to a non-zero value (or TRUE). If the value of expression is nonzero, statement1 and any other statements in the block are executed and the else-block, if present, is skipped. If the value of expression is zero, then the if-block is skipped and the else-block, if present, is executed. Expressions that evaluate to non-zero are
SyntaxExampleif statement with an initializer
Visual Studio 2017 version 15.3 and later (available with /std:c++17): An if statement may also contain an expression that declares and initializes a named variable. Use this form of the if-statement when the variable is only needed within the scope of the if-block.
How To Use Printf In CppExample
In all forms of the if statement, expression, which can have any value except a structure, is evaluated, including all side effects. Control passes from the if statement to the next statement in the program unless one of the statements contains a break, continue, or goto.
The else clause of an
if..else statement is associated with the closest previous if statement in the same scope that does not have a corresponding else statement.
String Format In C Printfif constexpr statements
Visual Studio 2017 version 15.3 and later (available with /std:c++17): In function templates, you can use an if constexpr statement to make compile-time branching decisions without having to resort to multiple function overloads. For example, you can write a single function that handles parameter unpacking (no zero-parameter overload is needed):
See also
Selection Statements
Keywords switch Statement (C++) Comments are closed.
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