What is the printf
printf () function is a function of the output format, the general information for a predetermined output format according to the standard output device.
printf () function call format is: printf ( "" format string "", "argument list").
Output format, which is a function of generating language formatted output c (defined in stdio.h). For the terminal (display, console, etc.) output character. Format control data format described by the character to be output and composition. In addition to the text to be output can be used other than letters, numbers, spaces and symbols some numbers, you can also use some escape characters to indicate special meaning.
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Function
Generating formatted output function in c language (defined in stdio.h), which is not redirected to the terminal (display, console, etc.) output character.
printf () function
The basic syntax printf (format placeholder list, variable list);
In printf () function, determines the format placeholder way output, except the placeholder in the list, to occupy the first position with placeholders% d like, then after the variable values are sequentially filled, the foregoing accounting the placeholder.
For example: Assume that a value of 50, b a value of 78
printf ( "% d", a); This function statement variable a value representative of the output, because the format is only one list placeholders% d, so only a value on the input display screen 50 is output
printf ( "% d,% d", a, b) shows a function value output two variables a and b, and also requires a comma intermediate, which is determined by the output format, the format of a list of placeholders% D,% d, it means to output two variables, intermediate variables comma, when executed, will fill in the value of a first of the% d, b value filled in the second% d. The output is displayed on the screen is 50,78
printf ( "a =% d, b =% d", a, b) format placeholder is a =% d, b =% d where a =, b = which will directly output the back values of a, b, respectively, fill two percent before the location. The output displayed on the screen is a = 50, b = 78
What is scanf
scanf () is a function in C language input. Like the printf function, it has been declared in the header file stdio.h years, so when using scanf function to add #include "stdio.h". It is a function of the input format, i.e. the format specified by the user from the keyboard to input data into the variable specified.
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Function prototype
1int scanf (const char * restrict format, ...);
Function scanf () is the standard input stream from the stdio (standard input device, typically a keyboard point) is read as a routine general purpose format can be read into a plurality of character described, and stored in the corresponding variable addresses. [1] The first argument is a format string that specifies the format of the input, and the format specifier is parsed and input information corresponding to the location indicated by the pointer stored in the position corresponding to the variable argument list. Each non-null pointer claims, and sequentially correspond to eleven string formatter.
Note the use of scanf function.
Scanf general syntax for function scanf (format list placeholders, variable address list), common formats have placeholders% d (integer),% f (floating-point) and the like.
Example: 1) Enter an integer value to the variable a: scanf ( "% d", & a); // note has a front & take address character, since the syntax is claimed herein address of the variable.
2) two output values are assigned to integer variables a, b
You can use two function scanf statement to achieve:
scanf ( "% d", & a); scanf ( "% d", & b);
The main drawback of such an approach is cumbersome, several variables need to write a few scanf, when the input data between two data can be separated by a space or carriage return.
You can also use a function scanf statement to achieve:
scanf ( "% d% d", & a, & b); //% d Notice the two is placed in a double quotation mark, does not require the use of any intermediate separator, the input data during program execution, the user can use the back space or the two numbers separated by car.
Particular attention to that: if the write scanf ( "% d,% d", & a, & b); when the user input data, must also be intermediate the two spaced apart input data. Technology area
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