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// do some non-destructive read tests relating text files
#include <stdio.h>
#include <string.h>
static void readchars( FILE *fd ) {
int c;
while ( (c = fgetc(fd)) != EOF ) {
printf("c = %d", c);
if ( c == 10 ) {
printf(" LF \\n");
}
if ( c == 13 ) {
printf(" CR \\r");
}
printf("\n");
}
}
static void readlines( FILE *fd ) {
char line[256];
while ( fgets(line, 255, fd) != NULL ) {
int len = strlen(line);
printf("line = %s", line);
if ( len >= 2 ) {
printf(" char[n - 1] = %d char[n] = %d\n",
line[len-2], line[len-1]);
} else if ( len >= 1 ) {
printf(" char[n] = %d\n",line[len-1]);
} else {
printf("empty string\n");
}
}
}
int main( int argc, char **argv ) {
// check usage
if ( argc != 2 ) {
printf("usage: %s file\n", argv[0]);
return -1;
}
char file[256];
strcpy( file, argv[1] );
FILE *fd;
// open a file in (default) text mode
printf("TEXT MODE (DEFAULT) by character\n\n");
fd = fopen( file, "r" );
if ( fd != NULL ) {
readchars( fd );
fclose(fd);
} else {
printf("Cannot open %s\n", file);
}
printf("\n");
// open a file in (explicit) text mode
printf("TEXT MODE (EXPLICIT) by character\n\n");
fd = fopen( file, "rt" );
if ( fd != NULL ) {
readchars( fd );
fclose(fd);
} else {
printf("Cannot open %s\n", file);
}
printf("\n");
// open a file in (explicit) binary mode
printf("BINARY MODE (EXPLICIT) by character\n\n");
fd = fopen( file, "rb" );
if ( fd != NULL ) {
readchars( fd );
fclose(fd);
} else {
printf("Cannot open %s\n", file);
}
printf("\n");
// open a file in (default) text mode
printf("TEXT MODE (DEFAULT) by line\n\n");
fd = fopen( file, "r" );
if ( fd != NULL ) {
readlines( fd );
fclose(fd);
} else {
printf("Cannot open %s\n", file);
}
printf("\n");
// open a file in (explicit) text mode
printf("TEXT MODE (EXPLICIT) by line\n\n");
fd = fopen( file, "rt" );
if ( fd != NULL ) {
readlines( fd );
fclose(fd);
} else {
printf("Cannot open %s\n", file);
}
printf("\n");
// open a file in (explicit) binary mode
printf("BINARY MODE (EXPLICIT) by line\n\n");
fd = fopen( file, "rb" );
if ( fd != NULL ) {
readlines( fd );
fclose(fd);
} else {
printf("Cannot open %s\n", file);
}
printf("\n");
return 0;
}