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 20
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 *name[2]={NULL,NULL};
» for ( int i=0;i<2; ++i) {
»printf("Player %d please enter your first name\n", i+1);
»namei=readaword();
}
»printf("Welcome %s and %s.\n", name0, name1);
» return 0;
}
Memory
Allocated memory
128
129
130
131
132
133
'_'
' '
'_'
' '
':'
'\0'
144
145
146
147
148
' '
' '
' '
' '
'\0'
readaword()
280
281
282
283
284
285
286
287
output = NULL
len = 43
288
289
290
291
292
293
294
295
input = ' ' '\0' '\0' '\0'
'\0'
'\0'
'\0'
'\0'
296
297
298
299
300
301
302
303
' '
'\0'
'\0'
'\0'
'0'
'p'
' '
' '
304
305
306
307
'G'
' '
' '
' '
readaword()
280
281
282
283
284
285
286
287
output = NULL
len = 43
288
289
290
291
292
293
294
295
input = ' ' '\0' '\0' '\0'
' '
'\0'
'\0'
'\0'
296
297
298
299
300
301
302
303
' '
'\0'
'\0'
'\0'
'0'
'p'
' '
' '
304
305
306
307
'G'
' '
' '
' '
main(): for()
344
345
346
347
i = 0
main()
348
349
350
351
name[0] =
352
353
354
355
name[1] =
NB: the actual memory address of each variable is
the address shown plus 4292505304 (0xFFDA6ED8).
The actual address of allocated memory is
the address shown plus 139555432 (0x8517268).
Show Advanced options
.
Input was:
Alice
Dave
Show output
(Before looking at the output,
work out what you think it put should be and see if you are right.)
Output
Player 1 please enter your first name
Player 2 please enter your first name
Welcome Alice and Dave.
