NJUPT-CSAPP/datalab-handout/ishow.c
2024-06-12 07:36:23 +08:00

75 lines
1.5 KiB
C

/* Display value of fixed point numbers */
#include <stdlib.h>
#include <stdio.h>
/* Extract hex/decimal/or float value from string */
static int get_num_val(char *sval, unsigned *valp) {
char *endp;
/* See if it's an integer or floating point */
int ishex = 0;
int isfloat = 0;
int i;
for (i = 0; sval[i]; i++) {
switch (sval[i]) {
case 'x':
case 'X':
ishex = 1;
break;
case 'e':
case 'E':
if (!ishex)
isfloat = 1;
break;
case '.':
isfloat = 1;
break;
default:
break;
}
}
if (isfloat) {
return 0; /* Not supposed to have a float here */
} else {
long long int llval = strtoll(sval, &endp, 0);
long long int upperbits = llval >> 31;
/* will give -1 for negative, 0 or 1 for positive */
if (valp && (upperbits == 0 || upperbits == -1 || upperbits == 1)) {
*valp = (unsigned) llval;
return 1;
}
return 0;
}
}
void show_int(unsigned uf)
{
printf("Hex = 0x%.8x,\tSigned = %d,\tUnsigned = %u\n",
uf, (int) uf, uf);
}
void usage(char *fname) {
printf("Usage: %s val1 val2 ...\n", fname);
printf("Values may be given in hex or decimal\n");
exit(0);
}
int main(int argc, char *argv[])
{
int i;
unsigned uf;
if (argc < 2)
usage(argv[0]);
for (i = 1; i < argc; i++) {
char *sval = argv[i];
if (get_num_val(sval, &uf)) {
show_int(uf);
} else {
printf("Cannot convert '%s' to 32-bit number\n", sval);
}
}
return 0;
}