#include #include #include //Constants #define PI 3.14 //Prepropressor directives //Function declaration int square (int alpha); int sum_up (int mm, int nn); //Variable scope int global_v = 0; //Static void under functions void s_v(); //Recursive function declaration int factoria(int numm); //Using Memory void test(int _k); //Pointers and Functions void swap (int *num3, int *num2); //Functions with array parameters int add_up (int *a0, int num_elements); //Functions that return an array int * get_evens(); //Structures struct students { int age; int grade; char name[40]; }; //Memory Management (Dynamic Arrays) typedef struct { int *elements; int size; int cap; } dyn_array; //A simple hello program int main() { printf("Hello!\n\nIt's Mofey,\nPlease don't mind the numbers, words and letters in the output of this program.\nThis is just a rough code for the aim of practicing the C language without errors.\n\n\n"); //Data Types printf("int: %ld\n", sizeof(int)); printf("float: %ld \n", sizeof(float)); printf("double: %ld \n", sizeof(double)); printf("char: %ld \n\n", sizeof(char)); //Variables int a, b; float salary = 3.234; char letter = 'X'; a = salary; b = 3; float c = a+b; /*For outputting floats(decimals) and char(characters) note the "%f" and "%c"*/ printf("%f\n",c); printf("%f", salary); printf("%c\n\n", letter); /*For outputting integers, note the "%d"*/ int x = 6; int y = 5; int z = x+y; printf("%d is strictly equal to ",z); //Variable scope //global_v has been defined before the main() global_v = x + y; printf("%d \n\n", global_v); //Constants const double zb = 3.14; printf("%f\n", zb); printf("%f\n\n", PI); /*putchar() Outputs a single character. char ac = getchar(); printf("You entered: "); putchar(ac);*/ /*scanf() scans input that matches format specifiers. int ae; Opening of the function below outputs the last added number as the sum of the users input given the the next function scanf("%d", &ae);*/ //printf("You entered: %d", a); int _a, _b; printf("Enter two numbers:"); scanf("%d %d", &_a, &_b); printf("\nSum: %d", _a+_b); /*Learning how to use different conversion type in C d decimal c character s string f float e scientific notation x hexadecimal*/ printf("\n\nColor: %s, Number: %d, float: %5.2f \n", "red", 42, 3.14159); //Color: red, Number: 42, float: 3.14 printf("Pi = %3.3f \n", 3.14159); //Pi = 3.14 printf("Pi = %9.5f \n", 3.14159); //Pi = 3.14159 printf("Pi = %-8.3f \n", 3.14159); //Pi = 3.141 printf("There are %d %s in the tree. \n\n", 22, "apples"); //There are 22 apples in the tree. //Division int i1 = 10; int i2 = 3; int quotient, remainder; float f1 = 4.2; float f2 = 2.5; float result; quotient = i1 / i2; // 3 remainder = i1 % i2; // 1 result = f1 / f2; // 1.68 printf("%d \n", quotient); printf("%d \n", remainder); printf("%f \n\n", result); //Type conversion (1) float price = 6.50; int increase = 2; float new_price; new_price = price + increase; printf("New price is %4.2f\n", new_price); /* Output: New price is 8.50 Note the format specifier includes 4.2 to indicate the float is to be printed in a space at least 4 characters wide with 2 decimal places.*/ //Type conversion (2) float average; int total = 23; int count = 4; average = (float) total / count; printf("%4.2f\n\n", average); //Increment & Decrement int dd, ee, ff; ff = 3; dd = ff--; //assign 3 to dd, then decrement ff to 2 printf("dd=%d \n", dd); ee = 3; dd = ++ee; //increment ee to 4, then assign 4 to dd printf("dd=%d \n", dd); printf("ee=%d \n\n", ee); //Examples of if statements (1) int score = 89; if (score >= 90){ printf("%s", "Top 10% \n"); } else if (score >= 80){ printf("%s", "Top 20% \n"); } else if (score > 75){ printf("%s", "You passed.\n"); } else { printf("%s", "You did not pass.\n"); } //Examples of if statements (2) int e; int d = 3; e = (d >= 5) ? 5 : d; printf("%d\n", e); /* Note: an expression that evaluates to a non-zero value is considered true.*/ int in_stock = 20; if (in_stock) { printf("Order received.\n\n"); } //Nested if statement example int profit = 1400; int clients = 18; int bonus; if(profit > 1000){ if(clients > 15){ } bonus = 100; } else{ bonus = 25; } printf("%d\n", bonus); /*Switch statement often provides a more elegant solution to if-else if and nested if statements.*/ int num = 3; switch (num) { case 1: printf("One\n"); break; case 2: printf("Two\n"); break; case 3: printf("Three\n"); break; default: printf("Not 1, 2, or 3.\n"); } /*Example of a switch statement of multiple cases with unique labels*/ switch (num) { case 1: case 2: case 3: printf("One, Two, or Three.\n\n"); break; case 4: case 5: case 6: printf("Four, Five, or Six."); break; default: printf("Greater than Six."); } //Logical operators char r = 'V'; if (!(r == 'x' || (r > 0 && r == 100))) printf("Roman numeral is not 10.\n\n"); /*Non-zero value is considered true and a 0 is false*/ //The while loop /*while (expression) { statements }*/ int hp = 5; while (hp > 0) { hp--; if (hp == 3) { continue; } else if (hp == 1) { break; } printf("%d\n", hp); } printf("\n");//to separate output lines //The do-while loop /*do { statements } while (expression);*/ int g = 1; do { printf("Count = %d\n", g); g++; } while (g < 8); printf("\n"); /*executes the loop statements before evaluating the expression to determine if the loop should be repeated*/ //For Loop /*for (initvalue; condition; increment) { statements; }*/ //Where initvalue stands for Initial value //Example of a nested loop int j; int h = 1; int eng = 5; int math = 5; for (; h < eng; h++) { for (j = 0; j <= math; j++) { printf("%d x %d = %d\n", h, j, h*j); } printf("\n");//blank line between tables } //Functions (2 examples); int m, results; m = 5; results = square(m); printf("%d squared is %d\n", m, results); int mm, nn, result_s; mm = 3; nn = 12; result_s = sum_up(mm, nn); printf("%d + %d = %d\n\n", mm, nn, result_s); //Static void under functions example int i; for (i = 0; i < 3; i++) { s_v(); } //Recursive function int _x = 5; printf("The factorial of %d is %d\n\n", _x, factoria(_x)); //Using loops to access array elements float purchases[] = {10.99, 14.25, 90.50}; float total1 = 0; int kk; /* total the purchases */ for (kk = 0; kk < 3; kk++) { total1 += purchases[kk]; } printf("Purchases total is %6.2f\n", total1); /* Output: Purchases total is 115.74 */ //Accessing a two-dimensional array int _c[2][3] = { {3, 2, 6}, {4, 5, 20} }; printf("Element 3 in row 2 is %d\n", _c[1][2]); /* 20 */ _c[1][2] = 25; printf("Element 3 in row 2 is %d\n", _c[1][2]); /* 25 */ //Using nested loops to access arrays int _aa[2][3] = { {3, 2, 6}, {4, 5, 20} }; int _bb, _cc; /* display array contents */ for (_bb = 0; _bb < 2; _bb++) { for (_cc = 0; _cc < 3; _cc++) { printf("%d ", _aa[_bb][_cc]); } printf("\n"); } // Using Memory //This is a modified version of the code provided by the "Using Memory" lesson by James Flanders on SoloLearn int _i = 0; // the use of %p preserves the format of &i as a pointer, so leading zeros are kept printf("\nThe address of i is %p\n", &_i); test(_i); printf("\nNow, let's check them both again...\n\n"); printf("The address of i is %p\n", &_i); test(_i); //Pointers in expressions int tm = 5; int mt; int *p = NULL; p = &tm; mt = *p + 2; /* y is assigned 7 */ mt += *p; /* y is assigned 12 */ *p = mt; /* x is assigned 12 */ (*p)++; /* x is incremented to 13 */ printf("\n\np is pointing to the value %d\n", *p); //Pointers on arrays using loops int a_p[5] = {22, 33, 44, 55, 66}; int *ptr = NULL; int ipr; ptr = a_p; for (ipr = 0; ipr < 5; ipr++) { printf("%d ", *(ptr + ipr)); } /*Pointers and Functions x and y have both been declared in line 54 and 55*/ printf("x is %d, y is %d\n", x, y); swap(&x, &y); printf("x is %d, y is %d\n\n", x, y); //Functions with array parameters int orderz[5] = {100, 220, 37, 16, 98}; printf("Total orders is %d\n", add_up (orderz, 5)); //Functions that return an array int *a_; int k; a_ = get_evens(); /* get first 5 even numbers */ for (k = 0; k < 5; k++){ printf("%d\n", a_[k]); } printf("\n"); //The string.h function char s1[ ] = "The grey fox"; char s2[ ] = " jumped."; strcat(s1, s2);//concats strings printf("%s\n", s1); printf("Length of s1 is %ld\n", strlen(s1));//returns length of a string strcpy(s1, s2);//interchanges the values of 2 strings printf("s1 is now %s \n\n", s1); //Structures /* declare two variables */ struct students ss1; struct students ss2; ss1.age = 19; ss1.grade = 9; sprintf(ss1.name, "John Bighimer"); ss2.age = 22; ss2.grade = 10; sprintf(ss2.name, "Batman Jokerson"); printf("Students: %s, %d\n", ss1.name, ss1.age); printf("Students: %s, %d\n\n", ss2.name, ss2.age); //Memory Management (Dynamic Arrays) dyn_array arr; int hi; /* initialize array */ arr.size = 0; arr.elements = calloc(1, sizeof(*arr.elements)); arr.cap = 1; /* room for 1 element */ /* expand by 5 more elements */ arr.elements = realloc(arr.elements, (5 + arr.cap)*sizeof(*arr.elements)); if (arr.elements != NULL) arr.cap += 5; /* increase capacity */ /* add an element and increase size */ if (arr.size < arr.cap) { arr.elements[arr.size] = 50; /* add element to array */ arr.size++; } else printf("Need to expand array."); /* display array elements */ for (hi = 0; hi < arr.cap; hi++) printf("Element %d: %d\n", hi, arr.elements[ hi ]); return 0; } /* Function definition */ int square (int alpha) { int n; n = alpha * alpha; return(n); } int sum_up (int mm, int nn) { mm += nn; return(mm); } //Static void function definition void s_v() { static int num_calls = 1; printf("static %d\n", num_calls); num_calls++; } //Recursive function definition int factoria(int numm) { if (numm == 1) /* base case */ return (1); else return (numm * factoria(numm - 1)); } //Using Memory void test(int _k){ printf("The address of k is %p\n", &_k); } //Pointers and Functions void swap (int *num3, int *num4) { int temp1; temp1 = *num3; *num3 = *num4; *num4 = temp1; } //Functions with array parameters int add_up (int *a0, int num_elements) { int tot = 0; int k1; for (k1 = 0; k1 < num_elements; k1++) { tot += a0[k1]; //Note that a0[k1] = *(a0+k1) } return (tot); } //Functions that return an array int * get_evens () { static int nums[5]; int k; int even = 0; for (k = 0; k < 5; k++) { nums[k] = even += 2; } return (nums); }

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