C Primer Plus 5/e 1.1 C

Transcription

1 C Primer Plus 5/e 1.1 C C C 2

2 2 C int main() // traditional rules int doors; int dogs; doors = 5; dogs = 3; // other statements int main() // C99 rules // some statements int doors; doors = 5; // first use of doors // more statements int dogs; dogs = 3; // first use of dogs // other statements 33

3 2 C n3 = n2 * n2; 47

4 3 C void main(int) / this program is perfect / cows, legs integer; printf( How many cow legs did you count?\n); scanf( %c, legs); cows = legs / 4; printf( That implies there are %f cows.\n, cows) Startled by the sudden sound, Sally shouted, By the Great Pumpkin, what was that! 101

5 C Primer Plus 5/e What is the radius of your pizza? 6.0 Your basic pizza parameters are as follows: circumference = 37.70, area = #define BEEP \a #define TEE T #define ESC \033 #define OOPS Now you have done it! /* the following is wrong */ #define TOES = 20 digits = fingers + TOES; digits = fingers + = 20; const const int MONTHS = 12; // MONTHS a symbolic constant for 114

6 4 scanf() 4.14 input.c // input.c -- when to use & #include <stdio.h> int main(void) int age; // variable float assets; // variable char pet[30]; // string printf( Enter your age, assets, and favorite pet.\n ); scanf( %d %f, &age, &assets); // use the & here scanf( %s, pet); // no & for char array printf( %d $%.2f %s\n, age, assets, pet); return 0; 133

7 5 shoe = 3.0; while (shoe < 18.5) foot = SCALE*size + ADJUST; printf( %10.1f %20.2f inches\n, shoe, foot); ++shoe; shoe = 2.0; while (++shoe < 18.5) foot = SCALE*shoe + ADJUST; printf( %10.1f %20.2f inches\n, shoe, foot); while shoe 3 true

8 bottles.c printf( Take one down and pass it around,\n ); printf( %d bottles of spring water!\n\n, count - 1); return 0; 100 bottles of spring water on the wall, 100 bottles of spring water! Take one down and pass it around, 99 bottles of spring water! 99 bottles of spring water on the wall, 99 bottles of spring water! Take one down and pass it around, 98 bottles of spring water! 1 bottles of spring water on the wall, 1 bottles of spring water! Take one down and pass it around, 0 bottles of spring water! 173

9 running.c // converts time to pure seconds time = S_PER_M * min + sec; // converts kilometers to miles distm = M_PER_K * distk; // miles per sec x sec per hour = mph rate = distm / time * S_PER_H; // time/distance = time per mile mtime = (double) time / distm; mmin = (int) mtime / S_PER_M; // find whole minutes msec = (int) mtime % S_PER_M; // find remaining seconds printf( You ran %1.2f km (%1.2f miles) in %d min, %d sec.\n, distk, distm, min, sec); printf( That pace corresponds to running a mile in %d min,, mmin); printf( %d sec.\nyour average speed was %1.2f mph.\n,msec, rate); return 0; This program converts your time for a metric race to a time for running a mile and to your average speed in miles per hour. Please enter, in kilometers, the distance run Next enter the time in minutes and seconds. Begin by entering the minutes. 36 Now enter the seconds. 191

10 9 ***************************************************************** 1) Fairfield Arms 2) Hotel Olympic 3) Chertworthy Plaza 4) The Stockton 5) quit ***************************************************************** 3 How many nights are needed? 1 The total cost will be $ ***************************************************************** Enter the number of the desired hotel: 1) Fairfield Arms 2) Hotel Olympic 3) Chertworthy Plaza 4) The Stockton 5) quit ***************************************************************** 4 How many nights are needed? 3 The total cost will be $ ***************************************************************** Enter the number of the desired hotel: 1) Fairfield Arms 2) Hotel Olympic 3) Chertworthy Plaza 4) The Stockton 5) quit ***************************************************************** 5 while ((status = scanf( %d, &code))!= 1 (code < 1 code > 5)) 395

11 C Primer Plus 5/e c z 3 int main(void) double q, x, duff(); /* declare in calling function */ int n;... q = duff(x,n);... double duff(u, k) /* declare in function definition */ double u; int k; double tor;... return tor; /* returns a double value */ 408

12 10 dates + 2 == &date[2] /* same address */ *(dates + 2) == dates[2] /* same value */ *(dates + 2) /* value of the 3rd element of dates */ *dates + 2 /* 2 added to the value of the 1st element */ 10.9 day_mon3.c /* day_mon3.c -- uses pointer notation */ #include <stdio.h> #define MONTHS 12 int main(void) int days[months] = 31,28,31,30,31,30,31,31,30,31,30,31; int index; for (index = 0; index < MONTHS; index++) printf( Month %2d has %d days.\n, index +1, *(days + index)); // same as days[index] return 0; 433

13 C Primer Plus 5/e show_array(rates, 5); show_array(locked, 4); // valid // valid mult_array(rates, 5, 1.2); mult_array(locked, 4, 1.2); // valid // not allowed double rates[5] = 88.99, , 59.45, , 340.5; double * const pc = rates; // pc points to beginning of the array pc = &rates[2]; // not allowed *pc = 92.99; // ok -- changes rates[0] double rates[5] = 88.99, , 59.45, , 340.5; const double * const pc = rates; pc = &rates[2]; // not allowed *pc = 92.99; // not allowed 450

14 10 int * p1; const int * p2; const int ** pp2; p1 = p2; // not valid -- assigning const to non-const p2 = p1; // valid -- assigning non-const to const pp2 = &p1; // not valid -- assigning non-const to const p2 = p1; // valid -- assigning non-const to const const int **pp2; int *p1; const int n = 13; pp2 = &p1; // not allowed, but suppose it were *pp2 = &n; // valid, both const, but sets p1 to point at n *p1 = 10; // valid, but changes const n 457

15 12 extern char permis = Y ; /* error */ static int svil = 1; // static variable, internal linkage int main(void) int traveler = 1; // external linkage static int stayhome = 1; // internal linkage int main() extern int traveler; // use global traveler extern int stayhome;..// use global stayhome 555

16 firms2.c /* films2.c -- using a linked list of structures */ #include <stdio.h> #include <stdlib.h> /* has the malloc prototype */ #include <string.h> /* has the strcpy prototype */ #define TSIZE 45 /* size of array to hold title */ struct film char title[tsize]; int rating; struct film * next; /* points to next struct in list */ ; int main(void) struct film * head = NULL; struct film * prev, * current; char input[tsize]; puts( Enter first movie title: ); while (gets(input)!= NULL && input[0]!= \0 ) current = (struct film *) malloc(sizeof(struct film)); if (head == NULL) /* first structure */ head = current; else /* subsequent structures */ prev->next = current; current->next = NULL; strcpy(current->title, input); puts( Enter your rating <0-10>: ); scanf( %d, &current->rating); while(getchar()!= \n ) continue; puts( Enter next movie title (empty line to stop): ); prev = current; if (head == NULL) printf( No data entered. ); else printf ( Here is the movie list:\n ); current = head; while (current!= NULL) printf( Movie: %s Rating: %d\n, current->title, current->rating); current = current->next; 665

17 14 union hold vala; vala.letter = R ; union hold valb = vala; // initialize one union to another union hold valc = 88; // initialize digit member of union union hold vald =.bigfl = 118.2; // designated initializer pu = &fit; x = pu->digit; // same as x = fit.digit fit.digit = 23; // 23 is stored in fit; 4 bytes used fit.bigfl = 2.0; // 23 cleared, 2.0 stored; 8 bytes used fit.letter = h ; // 2.0 cleared, h stored; 1 byte used fit.letter = A ; flnum = 3.02*fit.bigfl; // ERROR ERROR ERROR 671

18 C Primer Plus 5/e typedef struct complex float real; float imag; COMPLEX; typedef struct double x; double y; rect; rect r1 = 3.0, 6.0; rect r2; struct double x; double y; r1= 3.0, 6.0; struct double x; double y; r2; r2 = r1; typedef char (* FRPTC ()) [5]; 680

19 C Primer Plus 5/e val &= 0377; val = val & 0377; OR ( ) ( ) // ( ) // val = 0377; val = val 0377; OR ^ 696

20 16 C C #include <stdio.h> #include mystuff.h #include <stdio.h> #include hot.h #include /usr/biff/p.h /usr/biff 729

21 A printf Where are the parentheses? ;. 759

22 A #define P(X) printf( name: #X ; value: %d; address: %p\n, X, &X) #define _SKIP_ /* */ #ifndef _SKIP_ /* */ #endif #ifdef PR_DATE printf( Date = %s\n, DATE ); #endif enum days visit; 797