Code Created In Class To Help With Lab 6 October 8, 2018 CIS 1057 Fall 2018

Transcription

1 Key Takeaways from Class: Code Created In Class To Help With Lab 6 October 8, 2018 CIS 1057 Fall Always write programs in steps, not all at once. 2. Have a plan before you start writing code. 3. Don t be afraid to DESK CHECK your algorithms. Know the answer before the computer! 4. If code in one function gets too complicated, move it to its own function. Remember our rule of thumb: if it's more than 20 or so lines, it should probably be in a separate function. 5. Test your code frequently. Compiling is free! 6. Make only small changes and compile and run the program again. 7. Use print statements liberally to make it easy to track down problems and mistakes. 8. Use parameters to allow functions to perform different things based on input data. 9. Never submit any code for grading that you don t understand. You must know how it works! 10. When you submit this lab, make sure the program and function comments are clear and correct, and that all the requirements for the lab assignment are met. #include <stdio.h> #include <stdlib.h> #define CD #define AM #define YU 78 #define BO 190 #define PERCENTAGE 3 #define CD_TEXT "Carbon" #define AM_TEXT "Ammonia" #define YU_TEXT "Zombies" #define BO_TEXT "Zombies Too" int user_enters_input( void ); int is_substance_within_x_percent( int, double, int ); void check_substance( int ui, double sub, char *, int perc ); int main () int ui; /* holds the user input */ while ( 1 ) printf( "User entered %d.\n", ui ); check_substance( ui, CD, CD_TEXT, PERCENTAGE ); check_substance( ui, AM, AM_TEXT, PERCENTAGE ); check_substance( ui, YU, YU_TEXT, PERCENTAGE ); check_substance( ui, BO, BO_TEXT, PERCENTAGE ); return EXIT_SUCCESS;

2 int user_enters_input( void ) int var; printf( "Enter an observation or control-c to quit: " ); scanf( "%d", &var ); return var; int is_substance_within_x_percent( int user_input, double substanc, int percent ) double step1 = substanc * ( percent / ); printf( "TESTING SUBSTANCE %lf against observation %d.\n", substanc, user_input ); printf( " Step 1 = %lf\n", step1 ); double step2 = substanc + step1; double step3 = substanc - step1; short step4, step5; if ( user_input < 0 ) step4 = ( user_input >= step2 ); step5 = ( user_input <= step3 ); step4 = ( user_input <= step2 ); step5 = ( user_input >= step3 ); printf( " step2 = %lf, substance + step1.\n", step2 ); printf( " step3 = %lf, substance - step1.\n", step3 ); printf( " step4 = %d, ( user_input >= step2 ).\n", step4 ); printf( " step5 = %d, ( user_input <= step3 ).\n", step5 ); if ( step4 && step5 ) return 1; return 0; void check_substance( int ui, double sub, char *description, int perc ) int is_this_substance = is_substance_within_x_percent( ui, sub, perc ); if ( is_this_substance ) printf( "Found a matching substance!!! The substance is %s!\n", description ); puts( "" ); return;

3 When Compiling & Running [astro] ~/class-2018-oct-8 % cc try1.c [astro] ~/class-2018-oct-8 %./a.out Enter an observation or control-c to quit: 188 User entered 188. TESTING SUBSTANCE against observation 188. Step 1 = step2 = , substance + step1. step3 = , substance - step1. TESTING SUBSTANCE against observation 188. Step 1 = step2 = , substance + step1. step3 = , substance - step1. TESTING SUBSTANCE against observation 188. Step 1 = step2 = , substance + step1. step3 = , substance - step1. TESTING SUBSTANCE against observation 188. Step 1 = step2 = , substance + step1. step3 = , substance - step1. step4 = 1, ( user_input >= step2 ). Found a matching substance!!! The substance is Zombies Too! Enter an observation or control-c to quit: ^C [astro] ~/class-2018-oct-8 %

4 Alternate Version Some minor changes I'd make to the code, perhaps. 1. It might be better to keep the boiling point value and the tag together, so there's less chance of mistyping them. 2. Since we're creating an infinite loop for the while( ), we don't need the two separate invocations of the user_enters_input( ) function. Just one inside the loop will do. 3. Since the percentage isn t really needed as a parameter to the check_substance( ) function, we can remove that. 4. The lab assignment requires three formal parameters, so we still need it there, but we can just use it directly from the symbolic constant. #include <stdio.h> #include <stdlib.h> #define CD #define CD_TEXT "Carbon" #define AM #define AM_TEXT "Ammonia" #define YU 78 #define YU_TEXT "Zombies" #define BO 190 #define BO_TEXT "Zombies Too" #define PERCENTAGE 3 int user_enters_input( void ); int is_substance_within_x_percent( int, double, int ); void check_substance( int ui, double sub, char *description ); int main () int ui; /* holds the user input */ while ( 1 ) printf( "User entered %d.\n", ui ); check_substance( ui, CD, CD_TEXT ); check_substance( ui, AM, AM_TEXT ); check_substance( ui, YU, YU_TEXT ); check_substance( ui, BO, BO_TEXT ); return EXIT_SUCCESS;

5 int user_enters_input( void ) int var; printf( "Enter an observation or control-c to quit: " ); scanf( "%d", &var ); return var; int is_substance_within_x_percent( int user_input, double substanc, int percent ) double step1 = substanc * ( percent / ); printf( "TESTING SUBSTANCE %lf against observation %d.\n", substanc, user_input ); printf( " Step 1 = %lf\n", step1 ); double step2 = substanc + step1; double step3 = substanc - step1; short step4, step5; if ( user_input < 0 ) step4 = ( user_input >= step2 ); step5 = ( user_input <= step3 ); step4 = ( user_input <= step2 ); step5 = ( user_input >= step3 ); printf( " step2 = %lf, substance + step1.\n", step2 ); printf( " step3 = %lf, substance - step1.\n", step3 ); printf( " step4 = %d, ( user_input >= step2 ).\n", step4 ); printf( " step5 = %d, ( user_input <= step3 ).\n", step5 ); if ( step4 && step5 ) return 1; return 0; void check_substance( int ui, double sub, char *description ) int is_this_substance = is_substance_within_x_percent( ui, sub, PERCENTAGE ); if ( is_this_substance ) printf( "Found a matching substance!!! The substance is %s!\n", description ); puts( "" ); return;