char w[] = "final"; w[3] = '\0'; printf("w = %s\n", w); char *words = "tropical"; int i; for (i = 3; i >= 0; i--) printf("%c", i[words]);
w = finport
#include <stdio.h> int g = 0; void my_add(int x){ g += x; } void my_sub(int x){ g -= x; } int main() { int x = 1; switch (x++) { case 0: my_add(5); case 1: my_add(4); case 2: my_sub(3); case 3: my_add(2); default: my_sub(1); } printf("g = %d x = %d\n", g, x); return 0; }
g = 2 x = 2#include <stdio.h> int my_func(int i) { static int s; return i + s++; } int main() { int i, s; for (i = 0; (s = my_func(i)) < 3; i++); printf("i = %d s = %d\n", i, s); return 0; }
i = 2 s = 4int j = 0, n = 9; if (j++ && --n*1) { switch (++j) { case 0: n -= 4*j++; case 1: n -= 3*j++; case 2: n -= 2*j++; default: n -= 1*j++; } } else { switch (++j) { case 0: n += 3*j++; case 1: n += 2*j++; case 2: n += 1*j++; default: n += 4*j++; } } printf("j = %d n = %d\n", j, n);
j = 4 n = 23Assign the following type of pattern to a multidimensional array called my_arr, and print it with the following code. ANY SIZE!
0 0 0 00 0 0 10 0 1 10 1 1 1
#include <stdio.h> #define SIZE 4 int main() { int i, j; ///////////////////////////// //YOUR CODE HERE ///////////////////////////// for (i = 0; i < SIZE; i++) { for (j = 0; j < SIZE; j++) printf("%d ", my_arr[i][j]); printf("\n"); } return 0; }
#include <stdio.h> #define SIZE 4 int main() { int i, j;
int my_arr[SIZE][SIZE];
for (i = 0; i < SIZE; i++) for (j = 0; j < SIZE; j++) my_arr[i][j] = (i + j >= SIZE) ? 1 : 0; for (i = 0; i < SIZE; i++) { for (j = 0; j < SIZE; j++) printf("%d ", my_arr[i][j]); printf("\n"); } return 0; }
Write a program that scans input from a file and writes its output to another file, with names specified on the command line. The input file contains a list of (decimal) scores from 0 to N, inclusive, where N can be any integer. Assume N is defined. The output file should give a 'histogram' of the scores - print N lines, starting with the score and followed by a number of asterisks (*) equal to the number of times that score appeared in the input file. Round scores that are not integers to nearest value.
Input file (N=5) Output file
1 0: *
4 1: **
2 2: ***
3 3: ***
4 4: ****
4 5:
2
3
4
1
2
3
0Execution
$ ./a.out <INPUT_FILE_NAME> <OUTPUT_FILE_NAME>#include <stdio.h> #define N 5 int main(int argc, char *argv[]) { int i,j, hist[N+1] = {0}; double score; FILE *file_ptr = fopen(argv[1],"r"); while(fscanf(file_ptr,"%lf",&score) != EOF) hist[(int) (score+.5)]++; fclose(file_ptr); file_ptr = fopen(argv[2],"w"); for(i = 0; i <= N; i++) { fprintf(file_ptr,"%d: ",i); for(j = 0; j < hist[i]; j++) fprintf(file_ptr,"*"); fprintf(file_ptr,"\n"); } fclose(file_ptr); }
Write the following functions. Assume DECK_SIZE is defined at the top of the file and the function int generate_random() can be used to return a random integer between 0 and DECK_SIZE.
void fill_deck(int card_deck[]) /* fill_deck() puts the numbers 1 through DECK_SIZE into the card_deck array. * These values are inserted into the array in increasing order. Be careful * not to exceed the allowed array index values! * * Use array notation when implementing this function. You can assume that * card_deck is of size DECK_SIZE. */
void swap(int *x, int *y)
/* swap() swaps the integer values pointed to by x and y. */
void shuffle_deck(int card_deck[], int cards_in_pile, int num_swaps)
/* shuffle_deck() swaps two randomly chosen cards in the pile, and does this * num_swaps times. To choose the random cards, generate_random() is * called. To swap the cards, swap() is called. Assume there are * cards_in_pile cards in the pile to shuffle. * * Make sure that ALL * valid indices of the array are candidates for swapping, where the valid * indices are dependent on the number of cards in the pile, even though * card_deck has a length of DECK_SIZE. */
#define DECK_SIZE 52 void fill_deck(int card_deck[]) { int i; for(i = 0; i < DECK_SIZE; i++) card_deck[i] = i+1; }
void swap(int *x, int *y) { int temp = *x; *x = *y; *y = temp; }
void shuffle_deck(int card_deck[], int cards_in_pile, int num_swaps) { int i, card1, card2; for(i = 0; i < num_swaps; i++) { while((card1 = generate_random()) >= cards_in_pile); while((card2 = generate_random()) >= cards_in_pile); swap(&card_deck[card1], &card_deck[card2]); } }
Pick whatever kind of data you need. In the example below, we use doubles. After you call malloc(), use your variable, essentially, the same way you would use an array.
#include <stdio.h> #define MAX 5 int main() { // 1. Declare your pointer double *myData; // 2a. Use sizeof to get size of your datatype // 2b. Multiply by how many you need // 2c. Call malloc, pass the above value // 2d. Cast to pointer of the correct type myData = (double *) malloc(sizeof(double)*MAX); // 3. Free up the memory when you're done free(myData); }