Tất cả câu hỏi

#include <stdio.h>
#include <stdlib.h>

int main() {
    FILE *fp = fopen("data.txt", "r");
    char buffer[100];
    int number;

    if (fp != NULL) {
        fgets(buffer, sizeof(buffer), fp);
        fscanf(fp, "%d", &number);
        fclose(fp);
    }
    return 0;
}

void func(int *p){
    int j =11;
    *p = j;
}
int main() {
    int i = 1;
    int *p = &i;
    func(p);
    printf("%d,%d", i, *p);
    getchar();
    return 0;
}

int i=4;
int *p = &i;

int a[] = {1,2,3,4};
int i, s = 0;
for (i=0; i<4; ++i)
    s += a[i];
printf("%f", (float)(s/4));

#include <stdio.h>

int hours_and_minutes2(int total, int *pminutes) {
    return (*pminutes = total % 60, total / 60);
}

int main() {
    int minutes;
    printf("Hours: %d, Minutes: %d\n", hours_and_minutes2(135, &minutes), minutes);
    return 0;
}

#include <stdio.h>
int main(){
    int a=6,b=15;
    int* ptr1= &a, *ptr2=&b;
    *ptr1 +=12-b+ (*ptr2);
    *ptr2 = b + a- 2*(*ptr1);
    printf("%d, %d, %d", a,b,b+a*3);
}

#include <stdio.h>
void level2(int** ppa)
{
    printf("%d\n", **ppa);
}
void level1(int* pa)
{
    level2(&pa);
}
main()
{
    int a = 10;
    level1(&a);
}

#include <stdio.h>
int change(int a)
{
    a =10;
    return a;
}
void main()
{
    int i=5;
    i = change(i);
    printf("%d",i);
}

double g (double x, double y){
    return (x - 2)*(x - 2) + y*y;
}