1. Basic Knowledge 1. The basic data type occupies memory Char 1 bytes
Shot 2 int 4Float 4Double 8
Long 4 or 8 (32-bit operating system 4 bytes, 64 bits accounted for 8 bytes) 2. variable naming: Only numbers, letters, underscores, numbers cannot begin. 3. Some Xcode shortcut keys command + z undo deleted things
Command + shift +4
Command + r Run program COMMAND +/ Quick comment COMMAND + key to quickly let the cursor from the left side of the line to the right COMMAND + BACKSPACEDelete a row
Command + CTRL +Key aroundFast switching. hAnd. mFile
Command + SHIFT + NCreate a new public drive Command + comma Recall can be adjusted font size
Command +alt + curly braces move code up or down command +b only compile not run results 4. expressions are valued, so as long as the value is an expression 5. statement is the smallest unit of program execution, ending with a semicolon 6. A semicolon is also an empty statement 7. Escape character\ \ print \ percent print % 8. The main function is the entrance to the program, and the program execution starts with the main function and ends with the main function. input and output functions for 9.C languagesscanf("%d%c%d", &a,&b,&c); Precautions : 1. if the read-in data item type matches the format character, continue reading, otherwise, no longer view the remainder, return immediately 2. scanf ends with a big return 3. do not add \ n At the end of the scanf double quotation mark , whichwill offset the manual input //4.2 Meaning, 4 is a total of several numbers (including decimal points), 2 means reserved Several decimals
printf("%4.2f", 1.12); 9.x binary to decimal: Sum by weightdecimal to X-binary: Even in addition to the rewind remainder
Day0625_c basic knowledge of language
