Value and type of last evaluated expression: Address of array element: Address of array elementx: (none)
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Code
Header...
// Read in a long word, allocate the resulting character array
// Later we will encounter a more useful version of this function
#define BUFLEN 48
char * readaword(void){ ...
» char input[BUFLEN], *output=NULL;
» int len;
» if (scanf("%s", input)!=1) {
»fprintf(stderr, "Out of input!!\n");
»exit(99);
}
// Now allocate the final string and copy the input to it
»len=1+strlen(input);// +1 for closing '\0'
»output=malloc(len);// NB: sizeof *output == 1
» if (output==NULL) {
»fprintf(stderr, "Out of memory!\n");
»exit(98);
}
»strncpy(output, input, len);
» return output;
}
int main(){ ...
» char *word;
»printf("Please enter a long word\n");
»word=readaword();
»printf("Wow, %s\n\tis a long word!\n", word);
» return 0;
}
Memory
Allocated memory
128
129
130
131
132
133
134
135
' '
'Y'
' '
' '
' '
' '
' '
'i'
136
137
138
139
140
141
142
143
' '
' '
' '
' '
' '
' '
'G'
' '
144
145
146
147
148
149
150
151
' '
' '
' '
' '
' '
'@'
' '
'I'
152
153
154
155
156
157
158
159
' '
' '
' '
'+'
' '
' '
' '
'r'
160
161
162
'C'
' '
'\0'
readaword()
292
293
294
295
output = NULL
296
297
298
299
300
301
302
303
len = -144141781
input = 't' ' ' ' ' ' '
304
305
306
307
308
309
310
311
' '
'\0'
'\0'
'\0'
' '
'@'
' '
'\t'
312
313
314
315
316
317
318
319
' '
' '
' '
' '
'i'
' '
' '
' '
320
321
322
323
324
325
326
327
' '
'@'
' '
'\t'
' '
'\0'
'\0'
'\0'
328
329
330
331
332
333
334
335
'K'
' '
' '
' '
' '
'\0'
'\0'
'\0'
336
337
338
339
340
341
342
343
'\0'
'\0'
'\0'
'\0'
'\0'
'\0'
'\0'
'\0'
344
345
346
347
' '
' '
' '
' '
main()
376
377
378
379
word = -4293436223
NB: the actual memory address of each variable is
the address shown plus 4293436224 (0xFFE8A340).
The actual address of allocated memory is
the address shown plus 152142440 (0x9118268).
Show Advanced options
.
Input was:
supercalifragilisticexpialidocious
Show output
(Before looking at the output,
work out what you think it put should be and see if you are right.)
Output
Please enter a long word
Wow, supercalifragilisticexpialidocious
is a long word!
