# Lab 1 (four arithmetic exercises in primary school) and four arithmetic operations in primary school

Source: Internet
Author: User

Lab 1 (four arithmetic exercises in primary school) and four arithmetic operations in primary school

`# Include <stdio. h> # include <stdlib. h> int getChoice (); void showMenu (); void doExercise (int); int test (int); int getChoice () {int choice; scanf ("% d ", & choice); return choice;} void showMenu () {printf ("============================================= \ n "); printf ("\ n welcome to use the fourth arithmetic exercise SOFTWARE \ n"); printf ("\ n "); printf ("\ t1, addition exercise \ t2, subtraction exercise \ n"); printf ("\ t3, multiplication exercise \ t4, division exercise \ n "); printf ("\ t5, general exercise \ t0, exit system \ n"); printf ("\ n"); printf ("Enter your choice (0- -5): \ n "); printf ("\ n ======================================== \ n ");} void doExercise (int n) {int count = 0; int score = 0; // exercise score, initialized to 0 int I = 0; // counter of the number of exercise questions for (I = 1; I <= 10; I ++) {count = count + test (n); // call test (n) indirectly and recursively) score = count * 10;} printf ("You have done % d for ten questions in this exercise. The score is % d \ n", count, score );} /* function: test A Question */int test (int n) {int ranswer = 0; // The correct answer is int uanswer = 0; // user-entered answer int t = 0; // Temporary Variable char operation; // operation class int num1 = 0; // operand 1 int num2 = 0; // operand 2 srand (time (NULL); // initialize the random number seed num1 = rand () % 10; // obtain the random number num2 = rand () % 10 between 0-9; // enter the program function, if option 5 is selected, 1-4 represents a random generation of each operation method. if (n = 5) {n = rand () % 4 + 1;} switch (n) {case 1: operation = '+'; break; case 2: operation = '-'; break; case 3: operation = '*'; break; case 4: operation = '/'; break;}/* adds a statement to prevent "not enough subtraction". When Subtraction is selected and num1 is less than num2, swap two operands with temporary variables */if (operation = '-') & (num1 <num2) {t = num1; Num1 = num2; num2 = t;}/* prevents program vulnerabilities with a division of 0. When num2 is randomly set to 0, when num2 is forcibly set to 1 for division, the value of num1 is forcibly assigned to num1 * num2 to prevent division of */if (operation = '/') {if (num2 = 0) {num2 = 1;} num1 = num1 * num2; // prevent num1 from being divisible by num2} // output the test question itself and prompt the user to enter printf ("% d % c % d =", num1, operation, num2 ); scanf ("% d", & uanswer); // switch (operation) {case '+': ranswer = num1 + num2; break; case '-': ranswer = num1-num2; break; case '*': ranswer = num1 * num2; break; cas E '/': ranswer = num1/num2; break;} // judge. if yes, 1 is returned. if no result is returned, 0 if (uanswer = ranswer) {printf ("done! \ N "); return 1;} else {printf (" wrong! \ N "); return 0 ;}/// main function int main (void) {int choice = 0; // receives the user's selection // The cycle start function, do ...... While loop do {showMenu (); // display menu choice = getChoice (); // control the choice range if (choice <0 | choice> 5) {choice = 1; // force addition} if (choice = 0) {break; // The user selects 0 and exits the loop (exits the system)} doExercise (choice); // what to do, and start rating} while (choice! = 0); printf ("welcome to use this software. Goodbye! \ N "); return 0 ;}`

Although the Code is relatively simple to write and the functions have not yet met the requirements of the teacher, this well-defined writing method is quite preferred. Functions to be improved...

Related Keywords:
Related Article

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

## A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

• #### Sales Support

1 on 1 presale consultation

• #### After-Sales Support

24/7 Technical Support 6 Free Tickets per Quarter Faster Response

• Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.