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