1, simple program "Hello,word"

#include <stdio.h>//the. h file is a header file; Stdio refers to "standard input & Output", so it is necessary to include the header file when using the standard input/output function; header file definition: 1, #include <stdio.h > 2, #include "stdio.h"intMain ()//when there is a return value: Data type function name (), if required: Data type function name (data type variable); no return value: void function name (); if variable: void function name (data type variable){printf ("hello,word\n");//\ n is a line break, or two: printf ("Hello,word"); printf ("\ n");return 0;//Return indicates that the function returned from the callback to the key function continues execution, which can be returned with a return value specified by the argument following return. If function execution does not need to return the result of the calculation,}//It is also often necessary to return a status code to indicate whether the function is performing smoothly (-1 and 0 are the most commonly used status codes) if you have a return type definition in front of the name, such as int,double, you must have a return value,//In the case of void type, the return is not written, but the value cannot be returned even if it is written. 

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The functions contained in the stdio.h:

File access	Binary input/output	Non-formatted input/output	Format Input/Output	Format Input/Output	File location	Error handling	File operations
fopen Freopen Fflush Fclose	Fread Fwrite	Fgetc/getc Fputc/putc Ungetc Fgets Fputs	Fgetc/getc Fputc/putc Ungetc Fgets Fputs	scanf/fscanf/sscanf printf/fprintf/sprintf Perror	Ftell Fseek Fgetpos Fsetpos Rewind	Feof Ferror	Remove Rename Tmpfile

Common data type ranges:

1, simple program "Hello,word"