having trouble acquiring Int from "gets(*buffer)" - c

Question

So my tutor asked me to acquire an integer for a data struct , but 2 of the int parts im supposed to get , is via gets , im thinking he meant me to use gets(temp) // temp stand for char temp[50] and then perform x=strlen(temp);
here is my work so far :
#include<stdio.h>
#include<conio.h>
#include<string.h>
#define N 20
struct one
{
int ak;
char pin[N];
};
struct two
{
int data,mat[N];
struct one melos,item;
};
int main(void)
{
bool x=true;
int i;
char temp[N];
struct one person;
struct two memb;
/*GETTING VARS*/
gets(person.pin);
gets(memb.item.pin);
gets(memb.melos.pin);
person.ak=(int)gets(temp);
memb.data=(int)gets(temp);
for(i=0;i<N;i++)
scanf("%d",&memb.mat[i]);
scanf("%d",&memb.melos.ak);
scanf("%d",&memb.item.ak);
putchar('\n');
/*CHECKING VARS*/
puts("Posting vars in Data Struct ""one"" \n");
printf("%d\n",person.ak);
puts(person.pin);
puts("Posting vars in Data Struct ""two"" \n");
printf("%d\n",memb.data);
putchar('\n');
for(i=0;i<N;i++)
printf("%d\t",memb.mat[i]);
printf("\n%d\n",memb.melos.ak);
puts(memb.melos.pin);
printf("%d\n",memb.item.ak);
puts(memb.item.pin);
puts("**********************\n---POST_END---");
return 1;
}

Answer 1

The return value of gets() is the pointer to the buffer passed if successful, and NULL if failed. It won't mean the integer read.
Also note that you shouldn't use gets(), which has unavoidable risk of buffer overrun.
You will have to convert the string read to integer.
Try this:
#include<stdio.h>
#include<stdlib.h> /* for using atoi() */
#include<string.h>
#define N 20
/* read one line while checking the size read */
char* safer_gets(char* outbuf, size_t max){
size_t idx = 0;
int input;
if(max == 0) return NULL;
while(idx + 1 < max && (input = getchar()) != EOF && input != '\n'){
outbuf[idx++] = input;
}
if (idx == 0 && input == EOF) return NULL;
outbuf[idx] = '\0';
return outbuf;
}
/* read one line and convert it to integer */
int get_int(void) {
char temp[N];
safer_gets(temp, sizeof(temp));
return atoi(temp);
}
struct one
{
int ak;
char pin[N];
};
struct two
{
int data,mat[N];
struct one melos,item;
};
int main(void)
{
int i;
struct one person;
struct two memb;
/*GETTING VARS*/
safer_gets(person.pin, sizeof(person.pin));
safer_gets(memb.item.pin, sizeof(memb.item.pin));
safer_gets(memb.melos.pin, sizeof(memb.melos.pin));
person.ak=get_int();
memb.data=get_int();
/* latter part omitted */
}

Answer 2

Avoid gets - I'm surprised your class mentions it because it's been removed from all of the recent C language specifications and now deprecated in C++11.
But if you must...
http://www.cplusplus.com/reference/cstdio/gets/
long int getIntegerWithGetS() {
char* end;
char* buffer = calloc( 1024, sizeof(char) ); // 1024 bytes should be enough
long int result;
bool got_result_yet = false;
while( !got_result_yet ) {
gets( buffer ); // DANGER WILL ROBINSON
result = strtol( buffer, &end, 10 );
if( result == 0 ) {
if( end != buffer ) {
result = 0;
got_result_yet = true;
}
} else {
if( result != LONG_MAX && result != LONG_MIN && errno != ERANGE ) got_result_yet = true;
}
}
free(buffer);
return result;
}
Note how I call my code in a loop so we will persist until we get valid input from the user. I start off calling gets (to fill the buffer), then using strtol to convert the human-readable text in buffer to an actual computer int value - note that strtol is more powerful than atoi and uses long int instead of int as its declared type. Then the code checks for the strtol error conditions (in case a user types in "0" when the function returns 0 on failure anyway).
I don't return immediately, because the buffer must be free'd before execution leaves the scope, otherwise that buffer will remain unallocated and so leaked.