C Quiz 2

/*
* sizeof(char) = 1
* sizeof(int) = sizeof(float) = 4
* sizeof(double) = sizeof(T*) = 8
*/
struct S{ int i; char c; float f; double d; };

#include <stdio.h>
int main(){
 printf("%zu, %zu", sizeof(struct{ char c; char *s; }), sizeof(struct{ char c1; char *s; char c2; }));
 return 0;
}

#include <stdio.h>
int main(){
 printf("%zu, %zu", sizeof(struct{ double d; void *p; }*), sizeof(struct{ char c1[6]; double d; int i[3]; char c2[5]; }));
 return 0;
}

#include <stdio.h>
int main(){
 printf("%zu, %zu", sizeof(union{ char c1; char c2; char c3; }), sizeof(union{ char c, s[2]; }), sizeof(union{ char (*s)[2], c; });
 return 0;
}

#include <stdio.h>
int main(){
 printf("%zu, ", sizeof(struct{ char c[5]; int i[2]; union{ void *p[2]; char c[8]; } u; struct{ char c1[2], float f[2]; char c2[6]; } s; }));
 printf("%zu, ", sizeof(union{ char *(*pc)[4]; int (*pf[2])(void); struct{ float (*(*pf)[2])(void); char c; } s; union{ char c[4]; int i; } u; }));
 printf("%zu\n", sizeof(union{ struct{ int i; union{ struct{ char c; int (*i[2])[3]; } s; char c[17]; } u; char c; } s; char *(*c[3])[4][5]; }));
 return 0;
}

#include 
int main(){
 // int i; if(i) printf("non-zero"); // option 1
 // int *p = malloc(1); // option 2
 // int *p = realloc(NULL, 0); // option 3
 // int arr[3][3] = {0}; printf("%d", arr[1][5]); // option 4
 return 0;
}

#include <stdio.h>
int main(){
 int arr[] = {0, 1, 2, 3, 4, 5};
 int (*arr2)[3] = (int*[3])arr;
 arr2[1][1] = -1;
 int *arr3[3] = {arr, arr+2, arr+4};
 arr3[1][1] = -2;
 for(int i=0; i<6; ++i) printf("%d ", arr[i]);
}

#include <stdio.h>
int main(){
 // int i = 1; signed char c = (char)i; // option 1
 // int i = 1; unsigned char c = (char)i; // option 2
 // const int i = 1; *(int*)&i = 2; // option 3
 // signed int i = -1; ++*(unsigned int*)&i; // option 4
 return 0;
}

#include <stdio.h>

int randint(){
 int x;
 return x;
}

int main(){
 int x;
 scanf("&d", &x);
 if(x > 5) randint();
 else printf("test wasn't called");
 return 0;
}

#include <stdio.h>
// int i = i; // option 1
int main(){
 // int i = 0; int arr[3] = {i, ++i, --i}; // option 2
 // long int i = (long int)&i; // option 3
 // long int i = i; // option 4
 // int i = 0; int j = i++ + ++i; // option 5
 return 0;
}

const char *pc;
int const *pi;
float *const pf1;
float *const **const pf2;
const double *const (*pd)[2];

#include 

static int myint = 0;
static getg_myint(){ return myint; }

int main(){
 static int myint = 1, myint2 = 2;
 return 0;
}

#include <stdio.h>
// extern int i = 0; // option 1
// extern int foo(char); // option 2
int main(){
 // extern int var; // option 3
 // extern int bar(); // option 4
}

inline int add(int a, int b){ return a+b; }

#include <stdio.h>
int main(){
 volatile int *pi = 0;
 restrict char *pc = 0;
 const volatile void *restrict p = 0;
 return 0;
}

extern "C" void test();
int main(){
 test();
 return 0;
}

#include 
// sizeof(char) = 1, sizeof(short) = 2, sizeof(int) = 4, sizeof(T*) = 8
int main(){
 int i = 0x01234567;
 printf("%d, %d", *(char*)&i, *((short*)&i+2));
 return 0;
}

#include 
// sizeof(char) = 1, sizeof(short) = 2, sizeof(int) = 4, sizeof(int*) = sizeof(long int) = 8
int main(){
 int i = 0x01234567, j = 0xaabbccdd;
 struct{ int i; int *p; } s = { .i=0xdeadbeef, .p=(int*)0xcafebabefee1f00d };
 printf("%d, %ld", *(int*)((short*)&j+1), *(long int*)((unsigned long long)&s.p-6));
 return 0;
}

#include 
// sizeof(signed int) = sizeof(unsigned int) = 4
int main(){
 if(1 && 2) printf("1");
 if(1 & 2) printf("2");
 if((signed)-1 >> 31 == 0xffffffff) printf("3");
 if((unsigned)-1 >> 31 == 1) printf("4");
 return 0;
}

#include <stdio.h>
int main(){
 if(1 || *(int*)1) printf("success\n");
 else printf("failure\n");

 if(*(int*)1 || 1) printf("success\n");
 else printf("failure\n");
 return 0;
}