Java C # placeholders in C

Java C # placeholders in C
It is common to splice a string in programming. The following is a summary: What is a placeholder? A placeholder occupies a fixed position, waiting for you to add the content symbol to it. 1. java: copy the code package com. amos; import java. text. messageFormat;/*** Created by amosli on 14-7-24. */public class Test {public static void main (String args []) {// concatenate a string common method String name = "amosli"; // Method 1: string result = "hello," + name; System. out. println (result); // hello, amosli // Method 2: result = "hello ,". concat (name); System. out. println (result); // hello, amosli/ /Method 3: result = String. format ("% d % s", 200, "Yuan"); System. out. println (result); // $200 // Method 4: result = MessageFormat. format ("hi, {0}, I am {1}", "Jack", "Amosli"); System. out. println (result); // hi, Jack, I am Amosli} copy the code. Note: method 1 should be the most commonly used and use the + connector directly; method 2: Use the concat () method of the String class for connection, which is similar to the + number. Method 3. the placeholder is used, and the String is used in the third method. the format () method. Note that the content to be replaced must be % s in general, and % d in general. in method 4, {n} is directly used, where n represents the order of parameters, which is very similar to that in C. 2.C# Medium Static void Main () {string c = "hello, amosli"; string m = String. format ("{0}", c); // output Console in string Format. writeLine (m); // hello, amosli: letter meaning C or c Currency format D or d Decimal format (Decimal integer, do not match., for example, 1234 will be changed to 1, 234P, or p Percentage percentile format R or r Round-trip Round (for floating point only) make sure that a number is converted into a string and then converted back to the same number X or x Hex hexadecimal format. For example Under (see cs_6.cs) static void Main () {int I = 12345; Console. writeLine ("{0: C}", I); // currency Console. writeLine ("{0: D}", I); // Console in decimal number. writeLine ("{0: E}", I); // scientific and technological method Console. writeLine ("{0: F}", I); // floating point representation Console. writeLine ("{0: G}", I); // G or g General common format Console. writeLine ("{0: N}", I); // N or n use commas to separate thousands of digits} copy the code. Note: if you use the @ symbol. he will ignore all escape characters. that is, {1} is {1} rather than the placeholder. that is, "@ {1}" is not recognized as a placeholder. 3. the placeholder in C copies the format placeholders in the C language: % a, % Read a floating point value (valid only for C99) % c read a character % d read a decimal integer % I read a decimal, octal, hexadecimal integer % o read an octal integer % x, % X reads a hexadecimal integer % s into a string, ending with spaces, tabs, or line breaks. % F, % F, % e, % E, % g, and % G are used to input real numbers. They can be input in decimal or exponential form. % P read a pointer % u read an unsigned decimal integer % n equal to the number of characters % [] scanned Character Set % read % symbol format input and output example scanf ("% d, % d, % d ", & a, & B, & c); // enter three integers from the keyboard, and use commas to separate scanf (" % c ", & s ); // enter a character scanf ("% f", & f) from the keyboard; // enter a floating point data printf ("% d \ n", a) from the keyboard ); // output an integer printf ("% f \ n", B); // output a floating point number printf ("% s \ n", c ); // output a copy of a character code can basically see three very similar, Java and C # basically still copy C language.