Linux C machine exercises

File read/write operations

Fopen fclose fgetc fputc

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# Include <stdio. h> # Include <Stdlib. h> Int  Main () {File * FP;  Char  Ch;  If (FP = fopen ( "  File.txt  " , "  W " ) = NULL) //  If the file does not exist, it is automatically created. No parentheses should be missing !!  {Printf (  "  Cannot open this file! \ N  "  ); Exit (  0  );}  Else  {Printf (  "  File Open successfully! ----- Writeonly \ n  " );} Printf (  "  Input character from keyboard and end input with character '#' \ n  "  );  While ( 1  ) {Ch = Getchar ();  If (CH = '  #  '  )  Break ;  Else  {Fputc (CH, FP );}}  If (Fclose (FP) = 0  ) {Printf (  "  File write successful and closed \ n  "  );}  If (FP = fopen ( "  File.txt  " , " R  " ) = Null) {printf (  "  Cannot open this file! \ N  "  ); Exit (  0  );}  Else  {Printf (  "  File Open successful ------- readonly! \ N  "  );} Printf ( "  Read from this file! \ N  "  );  While ( 1  ) {Ch = Fgetc (FP );  If (Ch! = EOF) printf (  "  % C  "  , CH );  Else              Break ;}  If (Fclose (FP) = 0  ) {Printf (  "  \ Nfile read successful and closed \ n  "  );}} 

Fgets fputs

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# Include <stdio. h> # Include <Stdlib. h> # Include < String . H>Typedef  Struct  {  Char Name [ 10  ];  Char College [ 20  ];} Student;  Int  Main () {File * FP; Student Stu; Student stu_read;  If (FP = fopen ( "  File.txt " , "  W  " ) = Null) {printf (  "  Cannot open this file! \ N  "  ); Exit (  0  );}  Else  {Printf (  "  File Open successfully! ----- Writeonly \ n "  );} Printf (  "  Name:  "  ); Fgets (STU. Name,  10  , Stdin); printf (  "  College:  "  ); Fgets (STU. College,  20  , Stdin );  If (Fputs (STU. Name, FP )! = EOF & fputs (STU. College, FP )! =EOF) {printf (  "  Write successful! \ N  "  );}  If (Fclose (FP) = 0  ) {Printf (  "  File close \ n  "  );}  If (FP = fopen ( "  File.txt  " , "  R  " ) = Null) {printf (  "  Can not open this file! \ N  "  ); Exit (  0  );}  Else  {Printf (  "  File Open successfully! ----- Readonly \ n  " );} Fgets (stu_read.name,  10  , FP); fgets (stu_read.college,  20  , FP); printf (  "  Student name is % s \ n  "  , Stu_read.name); printf (  "  Student college is % s \ n  "  , Stu_read.college );  If (Fclose (FP) = 0 ) {Printf (  "  \ Nfile read successful and closed \ n  "  );}} 

Fread fwrite

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# Include <stdio. h> # Include <Stdlib. h> Int  Main (){  Struct  Student {  Char Number [ 6 ];  Char Name [ 20  ];  Char  Sex;  Int  Age;  Int  Score;} s [  2 ] = {{ "  00001  " , "  Peter " , '  M  ' , 19 , 250 },{ "  00002  " , "  Betty  " , '  F  ' , 18 ,268  }};  Struct Student ss [ 2  ];  Int  I, J; File * FP;  If (FP = fopen ( "  File. dat  " , "  WB +  " ) =Null) {printf (  "  Cannot open this file! \ N  "  ); Exit (  0  );} J = Sizeof ( Struct  Student );  For (I = 0 ; I <= 1 ; I ++ ){  If (Fwrite (& S [I], J, 1 , FP )! = 1  ) {Printf (  "  Write error! \ N  "  ); Exit (  0  ) ;}} Fflush (FP); printf (  "  Write successful! \ N  "  ); Rewind (FP); printf (  " Begin to read file... \ n  "  );  For (I = 0 ; I <= 1 ; I ++ ) {Fread ( & SS [I], J, 1  , FP); printf (  "  % S, % s, % C, % d, % d \ n  "  , Ss [I]. number, ss [I]. name, ss [I]. sex, ss [I]. age, ss [I]. score) ;}fclose (FP );}