# Exercise 7.4 - private version of scanf¶

## Question¶

Write a private version of scanf analogous to minprintf from the previous section.

```/* minscanf: minimalistic scanf function */
#include <stdarg.h>
#include <stdio.h>

void minscanf(char *fmt, ...);

int main(void) {

int i;
minscanf("%d", &i);
printf("minscanf input: %d\n", i);

char *a;
minscanf("%s", a);
printf("minscanf input: %s\n", a);

float f;
minscanf("%f", &f);
printf("minscanf input: %f\n", f);

int o;
minscanf("%o", &o);
printf("minscanf input in octal %o, in decimal %d\n", o, o);

int x;
minscanf("%x", &x);
printf("minscanf input in hex %x, in decimal %d\n", x, x);
return 0;
}

void minscanf(char *fmt, ...) {
va_list ap; /* points to each unnamed arg in turn */
char *p, *sval;
int *ival;
float *dval;

va_start(ap, fmt); /* make ap point to 1st unnamed arg */

for (p = fmt; *p; p++) {
if (*p != '%') {
continue;
}

switch (*++p) {
case 'd':
ival = va_arg(ap, int *);
char *d = "44";
sscanf(d, "%d", ival);
break;
case 'f':
dval = va_arg(ap, float *);
char *f = "5.33";
sscanf(f, "%f", dval);
break;
case 's':
sval = va_arg(ap, char *);
sscanf("test char", "%s", sval);
break;
case 'o':
ival = va_arg(ap, int *);
char *o = "011";
sscanf(o, "%o", ival);
break;
case 'x':
ival = va_arg(ap, int *);
char *x = "1a";
sscanf(x, "%x", ival);
break;
default:
putchar(*p);
break;
}
}
va_end(ap); /* clean up when done */
}
```