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50 righe
1.3 KiB
50 righe
1.3 KiB
#include <stdio.h>
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#define BUFSIZE 1024
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static char buf[BUFSIZE];
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/* *
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* readline - get a line from stdin
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* @prompt: the string to be written to stdout
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*
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* The readline() function will write the input string @prompt to
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* stdout first. If the @prompt is NULL or the empty string,
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* no prompt is issued.
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*
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* This function will keep on reading characters and saving them to buffer
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* 'buf' until '\n' or '\r' is encountered.
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*
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* Note that, if the length of string that will be read is longer than
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* buffer size, the end of string will be discarded.
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*
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* The readline() function returns the text of the line read. If some errors
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* are happened, NULL is returned. The return value is a global variable,
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* thus it should be copied before it is used.
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* */
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char *
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readline(const char *prompt) {
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if (prompt != NULL) {
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cprintf("%s", prompt);
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}
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int i = 0, c;
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while (1) {
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c = getchar();
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if (c < 0) {
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return NULL;
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}
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else if (c >= ' ' && i < BUFSIZE - 1) {
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cputchar(c);
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buf[i ++] = c;
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}
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else if (c == '\b' && i > 0) {
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cputchar(c);
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i --;
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}
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else if (c == '\n' || c == '\r') {
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cputchar(c);
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buf[i] = '\0';
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return buf;
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}
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}
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}
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