7. C program structure

1. Structure of a c program Any C Program consists of the following parts: Preprocessor part Main function. This consists of the following: The declaration part The Initialization part The Input Processing (Assignment, if/switch, calculations, or any other C statements that will be covered later) The Output Return (0) command This is shown in the diagram of the next slide. Dr. Soha S. Zaghloul 2

1. Structure of a c program - summarized Preprocessor part (#include, #define) Main function int main (void) { // declaration part // initialization part // input part // processing // output Return (0); } // end of main function Dr. Soha S. Zaghloul 3

1.1 declaration part Preprocessor part (#include, #define) Main function int main (void) { // declaration part int number1, number2, number3; char gender; double salary; // initialization part // input part // processing // output Return (0); } // end of main function Dr. Soha S. Zaghloul 4

1.2 initialization part Preprocessor part (#include, #define) Main function int main (void) { // declaration part // initialization part total = 0; // previously declared double product = 1.0; // undeclared char name[20] = “xxxxxxxxxxxxxxxx”; //undeclared // input part // processing // output Return (0); } // end of main function Dr. Soha S. Zaghloul 5

1.3 input part Preprocessor part (#include, #define) Main function int main (void) { // declaration part // initialization part // input part printf (“Enter the values of three integers\n”); scanf (“%d%d%d”, &number1, &number2, &number3); // processing // output Return (0); } // end of main function Dr. Soha S. Zaghloul 6

1.4 processing part Preprocessor part (#include, #define) Main function int main (void) { // declaration part // initialization part // input part // processing total = number1 + number2 + number3; // output Return (0); } // end of main function Dr. Soha S. Zaghloul 7

1.4 processing part (2) Preprocessor part (#include, #define) Main function int main (void) { // declaration part // initialization part // input part // processing total = total + number1; product = product * number2; // output Return (0); } // end of main function Dr. Soha S. Zaghloul 8

1.4 processing part (3) Preprocessor part (#include, #define) Main function int main (void) { // declaration part // initialization part // input part // processing if (total == 0) total = total + number1; else product = product * number1; // output Return (0); } // end of main function Dr. Soha S. Zaghloul 9

1.5 output part Preprocessor part (#include, #define) Main function int main (void) { // declaration part // initialization part // input part // processing // output printf (“Final Results are: “); printf (“Total = %d, Product = %f”, total, product); Return (0); } // end of main function Dr. Soha S. Zaghloul 10

2. Example (1) Write a complete program that calculates the average of three integer numbers. Input? number1 number2 number3 Type? integer value? Through scanf Output? average Type? double value? To be calculated // declaration part int number1, number2, number3; double average; // input part printf (“Enter the values of the three integers: \n”); scanf (“%d%d%d”, &number1, &number2, &number3); Dr. Soha S. Zaghloul 11

2. Example (1) – cont’d Write a complete program that calculates the average of three integer numbers. #include <stdio.h> int main (void) { // declaration part int number1, number2, number3; double average; // input part printf (“Enter the values of the three integers: \n”); scanf (“%d%d%d”, &number1, &number2, &number3); // processing part average = (number1 + number2 + number3) /3.0; // output part printf (“The average equals %f “, average); return (0); } // end of main Dr. Soha S. Zaghloul 12

2. Example (2) Write a complete program to select an operation based on the value of inventory. Increment total_paper by paper_order if inventory is ‘B’ or ‘C’; increment total_ribbon by ribbon_order if inventory is ‘E’, ‘F’, or ‘D’; increment total_label by label_order if inventory is ‘A’ or ‘X’. Do nothing if inventory is ‘M’. Display an error message if the value of inventory is not one of these eight letters. input? inventory paper_order ribbon_order label_order type? char integer value? Through scanf // declaration part char inventory; int paper_order, ribbon_order, label_order; Dr. Soha S. Zaghloul 13

2. Example (2) – cont’d Write a complete program to select an operation based on the value of inventory. Increment total_paper by paper_order if inventory is ‘B’ or ‘C’; increment total_ribbon by ribbon_order if inventory is ‘E’, ‘F’, or ‘D’; increment total_label by label_order if inventory is ‘A’ or ‘X’. Do nothing if inventory is ‘M’. Display an error message if the value of inventory is not one of these eight letters. #include <stdio.h> int main (void) { // declaration part char inventory; int paper_order, ribbon_order, label_order; // input part printf (“Enter inventory \n”); scanf (“%c”, inventory); Dr. Soha S. Zaghloul 14

2. Example (2) – cont’d #include <stdio.h> int main (void) { Write a complete program to select an operation based on the value of inventory. Increment total_paper by paper_order if inventory is ‘B’ or ‘C’; increment total_ribbon by ribbon_order if inventory is ‘E’, ‘F’, or ‘D’; increment total_label by label_order if inventory is ‘A’ or ‘X’. Do nothing if inventory is ‘M’. Display an error message if the value of inventory is not one of these eight letters. // declaration part char inventory; int paper_order, ribbon_order, label_order; // input part printf (“Enter inventory \n”); scanf (“%c”, inventory); // iniatlization part int total_paper = 0; // processing part switch (inventory) { case ‘B’: case ‘C’: printf (“Enter amount of ordered paper \n”); scanf (“%d”, &paper_order); total_paper = total_paper + paper_order; printf (“Total paper = %d”, total_paper); break; Dr. Soha S. Zaghloul 15

2. Example (2) – cont’d #include <stdio.h> int main (void) { Write a complete program to select an operation based on the value of inventory. Increment total_paper by paper_order if inventory is ‘B’ or ‘C’; increment total_ribbon by ribbon_order if inventory is ‘E’, ‘F’, or ‘D’; increment total_label by label_order if inventory is ‘A’ or ‘X’. Do nothing if inventory is ‘M’. Display an error message if the value of inventory is not one of these eight letters. // declaration part char inventory; int paper_order, ribbon_order, label_order; // input part printf (“Enter inventory \n”); scanf (“%c”, inventory); // iniatlization part int total_paper = 0, total_ribbon = 0; // processing part // continuation of the switch statement case ‘E’: case ‘F’: case ‘D’: printf (“Enter amount of ordered ribbon \n”); scanf (“%d”, &ribbon_order); total_ribbon = total_ribbon + paper_order; printf (“Total ribbon = %d”, total_ribbon); break; Dr. Soha S. Zaghloul 16

2. Example (2) – cont’d #include <stdio.h> int main (void) { Write a complete program to select an operation based on the value of inventory. Increment total_paper by paper_order if inventory is ‘B’ or ‘C’; increment total_ribbon by ribbon_order if inventory is ‘E’, ‘F’, or ‘D’; increment total_label by label_order if inventory is ‘A’ or ‘X’. Do nothing if inventory is ‘M’. Display an error message if the value of inventory is not one of these eight letters. // declaration part char inventory; int paper_order, ribbon_order, label_order; // input part printf (“Enter inventory \n”); scanf (“%c”, inventory); // iniatlization part int total_paper = 0, total_ribbon = 0, total_label = 0; // processing part // continuation of the switch statement case ‘A’: case ‘X’: printf (“Enter amount of ordered label \n”); scanf (“%d”, &label_order); total_label = total_label + label_order; printf (“Total label = %d”, total_label); break; Dr. Soha S. Zaghloul 17

2. Example (2) – cont’d #include <stdio.h> int main (void) { Write a complete program to select an operation based on the value of inventory. Increment total_paper by paper_order if inventory is ‘B’ or ‘C’; increment total_ribbon by ribbon_order if inventory is ‘E’, ‘F’, or ‘D’; increment total_label by label_order if inventory is ‘A’ or ‘X’. Do nothing if inventory is ‘M’. Display an error message if the value of inventory is not one of these eight letters. // declaration part char inventory; int paper_order, ribbon_order, label_order; // input part printf (“Enter inventory \n”); scanf (“%c”, inventory); // iniatlization part int total_paper = 0, total_ribbon = 0, total_label = 0; // processing part // continuation of the switch statement case ‘M’: break; default: printf (“Invalid input \n”); //invalid inventory value break; } // end of switch statement return (0); } //end of main Dr. Soha S. Zaghloul 18

2. Example (2) – cont’d // processing part // Using if statement if (inventory == ‘B’) || (inventory == ‘C’) { printf (“Enter amount of ordered paper \n”); scanf (“%d”, &paper_order); total_paper = total_paper + paper_order; printf (“Total paper = %d”, total_paper); } // (inventory == ‘B’) || (inventory == ‘C’) else if (inventory == ‘E’) || (inventory == ‘F’) || (inventory == ‘D’) printf (“Enter amount of ordered ribbon \n”); scanf (“%d”, &ribbon_order); total_ribbon = total_ribbon + paper_order; printf (“Total ribbon = %d”, total_ribbon); } // (inventory == ‘E’) || (inventory == ‘F’) || (inventory == ‘D’) else if (inventory == ‘A’) || (inventory == ‘X) printf (“Enter amount of ordered label \n”); scanf (“%d”, &label_order); total_label = total_label + label_order; printf (“Total label = %d”, total_label); } // (inventory == ‘A’) || (inventory == ‘X) else if (inventory != ‘M’) // what if (inventory == ‘M)? printf (“Invalid Input \n”) Dr. Soha S. Zaghloul 19

2. Example (3) The table below shows the normal boiling points of several substances. Write a program that prompts the user for the observed boiling point of a substance in ºC. The program then identifies the substance if the observed boiling point is within 5% (more or less) of the expected boiling point. If the data input is more than 5% higher or lower than any of the boiling points in the table, the program should output the message “Substance unknown”. Substance Expected Boiling Point (ºC) Water 100 Mercury 357 Copper 1187 Silver 2193 Gold 2660 Dr. Soha S. Zaghloul 20

2. Example (3) The table below shows the normal boiling points of several substances. Write a program that prompts the user for the observed boiling point of a substance in ºC. The program then identifies the substance if the observed boiling point is within 5% (more or less) of the expected boiling point. If the data input is more than 5% higher or lower than any of the boiling points in the table, the program should output the message “Substance unknown”. Substance Expected Boiling Point (ºC) Water 100 Mercury 357 Copper 1187 Silver 2193 Gold 2660 Dr. Soha S. Zaghloul 21

2. Example (3) Input? observed Type? double value? Through scanf Output? substance Type? string value? To be calculated #include <stdio.h> int main (void) { // declaration part int observed; char substance[20]; // input part printf (“Enter the observed boiling point: \n”); scanf (“%d”, &observed); return (0); } // end of main Dr. Soha S. Zaghloul 22

2. Example (3) The table below shows the normal boiling points of several substances. Write a program that prompts the user for the observed boiling point of a substance in ºC. The program then identifies the substance if the observed boiling point is within 5% (more or less) of the expected boiling point. If the data input is more than 5% higher or lower than any of the boiling points in the table, the program should output the message “Substance unknown”. Substance Expected Boiling Point (ºC) Water 100 Mercury 357 Copper 1187 Silver 2193 Gold 2660 water_plus5 = (100 * 0.05) + 100; water_minus5 = (100 * 0.05) – 100; if (observed >= water_minus5) && (observed <= water_plus5) strcopy (substance, “water”); Dr. Soha S. Zaghloul 23

2. Example (3) The table below shows the normal boiling points of several substances. Write a program that prompts the user for the observed boiling point of a substance in ºC. The program then identifies the substance if the observed boiling point is within 5% (more or less) of the expected boiling point. If the data input is more than 5% higher or lower than any of the boiling points in the table, the program should output the message “Substance unknown”. Substance Expected Boiling Point (ºC) Water 100 Mercury 357 Copper 1187 Silver 2193 Gold 2660 in the same way, calculate: mercury_plus5, mercury_minus5, copper_plus5, copper_minus5, silver_plus5, silver_minus5, gold_plus5, gold_minus5 Dr. Soha S. Zaghloul 24

Don’t forget to declare your variables!!! 2. Example (3) The table below shows the normal boiling points of several substances. Write a program that prompts the user for the observed boiling point of a substance in ºC. The program then identifies the substance if the observed boiling point is within 5% (more or less) of the expected boiling point. If the data input is more than 5% higher or lower than any of the boiling points in the table, the program should output the message “Substance unknown”. Substance Expected Boiling Point (ºC) Water 100 Mercury 357 Copper 1187 Silver 2193 Gold 2660 Don’t forget to declare your variables!!! Dr. Soha S. Zaghloul 25

Complete the if statement…and conclude your program 2. Example (3) The table below shows the normal boiling points of several substances. Write a program that prompts the user for the observed boiling point of a substance in ºC. The program then identifies the substance if the observed boiling point is within 5% (more or less) of the expected boiling point. If the data input is more than 5% higher or lower than any of the boiling points in the table, the program should output the message “Substance unknown”. Substance Expected Boiling Point (ºC) Water 100 Mercury 357 Copper 1187 Silver 2193 Gold 2660 Complete the if statement…and conclude your program Dr. Soha S. Zaghloul 26

2. Example (4) Write a program that calculates and prints the bill for Riyadh’s power consumption. The rates vary depending on whether the user is residential, commercial, or industrial. A code of R corresponds to a Residential, C corresponds to a Commercial, and I to Industrial. Any other code should be treated as an error. The program should read the power consumption rate in KWH (Kilowatt per Hour); then it calculates the due amount according to the following: The rate is SAR 5 per KWH for Residential, SAR 10 per KWH for Commercial and SAR 20 per KWH for Industrial. Dr. Soha S. Zaghloul 27

2. Example (4) – input Write a program that calculates and prints the bill for Riyadh’s power consumption. The rates vary depending on whether the user is residential, commercial, or industrial. A code of R corresponds to a Residential, C corresponds to a Commercial, and I to Industrial. Any other code should be treated as an error. The program should read the power consumption rate in KWH (Kilowatt per Hour); then it calculates the due amount according to the following: The rate is SAR 5 per KWH for Residential, SAR 10 per KWH for Commercial and SAR 20 per KWH for Industrial. Dr. Soha S. Zaghloul 28

2. Example (4) – input Write a program that calculates and prints the bill for Riyadh’s power consumption. The rates vary depending on whether the user is residential, commercial, or industrial. A code of R corresponds to a Residential, C corresponds to a Commercial, and I to Industrial. Any other code should be treated as an error. The program should read the power consumption rate in KWH (Kilowatt per Hour); then it calculates the due amount according to the following: The rate is SAR 5 per KWH for Residential, SAR 10 per KWH for Commercial and SAR 20 per KWH for Industrial. Dr. Soha S. Zaghloul 29

2. Example (4) – output Write a program that calculates and prints the bill for Riyadh’s power consumption. The rates vary depending on whether the user is residential, commercial, or industrial. A code of R corresponds to a Residential, C corresponds to a Commercial, and I to Industrial. Any other code should be treated as an error. The program should read the power consumption rate in KWH (Kilowatt per Hour); then it calculates the due amount according to the following: The rate is SAR 5 per KWH for Residential, SAR 10 per KWH for Commercial and SAR 20 per KWH for Industrial. Dr. Soha S. Zaghloul 30

2. Example (4) – processing Write a program that calculates and prints the bill for Riyadh’s power consumption. The rates vary depending on whether the user is residential, commercial, or industrial. A code of R corresponds to a Residential, C corresponds to a Commercial, and I to Industrial. Any other code should be treated as an error. The program should read the power consumption rate in KWH (Kilowatt per Hour); then it calculates the due amount according to the following: The rate is SAR 5 per KWH for Residential, SAR 10 per KWH for Commercial and SAR 20 per KWH for Industrial. Dr. Soha S. Zaghloul 31