3. Select structure program design and structure program design.

3. Select structure program design and structure program design.

The if statement is used to implement the selection structure (with a range) of two branches. The switch statement is used to implement the selection structure of multiple branches (preferably a fixed value)

For example

// Condition branch if // int num1 = 20; // int num2 = 10; // if (num1> num2) // {// printf ("num1> num2 \ n ");//}//

Multiple if

// Multiple if ...... else if ..... else. // float score; // printf ("Enter the score \ n"); // scanf ("% f", & score ); //// if (score> = 90) & (score <= 100) {printf ("Excellent \ n "); ///} else if (score> = 80) & (score <90) {printf ("good \ n ");} // else if (score> = 60) & (score <70) {printf ("Medium \ n ");} // else {printf ("difference \ n ");////}

Switch statement

Enter the number of days in the year/month Query

// Int year, month; // printf ("Enter year: \ n"); // scanf ("% d", & year ); // printf ("Enter the month: \ n"); // scanf ("% d", & month); // switch (month) {// case 1: // case 3: // case 5: // case 7: // case 8: // case 10: // case 12: // printf ("31 days this month \ n"); // break; // case 4: // case 6: // case 9: // case 11: // printf ("30 days this month \ n"); // break; // case 2: /// if (year % 4 = 0 & year % 100! = 0) | (year % 400 = 0) {// printf ("this month is 29 days of the leap year \ n "); //} else {// printf ("this month is 28 days of the year \ n"); //} // break; // default: printf ("the month you entered is incorrect \ n"); // break ;//}////

Query for vowels

// Char a; // printf ("Enter the letter \ n"); // scanf ("% c", & a); // switch () {// case 'A': // case 'E': // case 'I': // case 'O': // case 'U ': // case 'A': // case 'E': // case 'I': // case 'O': // case 'U ': // printf ("it is a vowel letter \ n"); // break; // default: printf ("not a vowel letter \ n"); // break; //}//

Arithmetic Operation

// Result indicates the first number, the second number, and the fourth number of operands. // The second number, the second number, and the second number of operands. // int result = 0, num1, num2; // char success; // int flag = 1; // printf ("enter two numbers \ n"); // scanf ("% d ", & num1, & num2); // printf ("Please input the operand :( +,-, *,/) \ n"); // scanf ("% c ", & Environment); // switch (Environment) {// case '+': // result = num1 + num2; // break; // case '-': // result = num1-num2; // break; // case '*': // result = num1 * num2; // break; // case '/': // result = num1/num2 ;// Break; // default: // flag = 0; // break; //} // if (flag = 1) {// printf ("result = % d \ n", result); //} // else // {// printf ("your input is incorrect! \ N ");//}

 

 

 

You can see it later.

 

 

 

 

 

 

// Question 6 // float x, y; // printf ("Enter the value of x \ n"); // scanf ("% f", & x ); // if (x <1) {// printf ("Y value: %. 2f \ n ", y = x); //} else if (1 <= x & x <10) // {printf (" Y value: %. 2f \ n ", y = 2 * x-1); //} // else {// printf (" the value of Y is: %. 2f \ n ", y = 3 * X-11); // question 7 // float gz, grs, g; // printf ("Enter your salary \ n"); // scanf ("% f", & g); // gz = g-300-3500; // if (g> 0) {// if (gz> 0 & gz <= 1500) {// printf ("your personal tax is: %. 2f \ n ", grs = gz * 0.03); //} else if (gz> 1500 & gz <= 4500) // {printf ("your personal tax is: %. 2f \ n ", grs = gz * 0.1-105); //} else if (gz> 4500 & gz <= 9000) // {printf ("your personal tax is: %. 2f \ n ", grs = gz * 0.2-555); //} else if (gz> 9000 & gz <= 35000) // {printf ("your personal tax is: %. 2f \ n ", grs = gz * 0.25-1005); //} else if (gz> 35000 & gz <= 55000) // {printf ("your personal tax is: %. 2f \ n ", grs = gz * 0.30-2755); //} else if (gz> 55000 & gz <= 80000) // {printf ("your personal tax is: %. 2f \ n ", grs = gz * 0.35-5505); //} else if (gz> 80000 )// {Printf ("your personal tax is: %. 2f \ n ", grs = gz * 0.45-13505); //} else {// printf (" no money \ n "); ///} //} else {// printf ("You're ugly !! \ N "); // Question 8 // double jine, jiangjin; // printf (" Enter your amount (RMB) \ n "); // scanf ("% lf", & jine); // if (jine> 0) {// if (jine <= 10) {// printf ("Your reward is: %. 4f RMB \ n ", jiangjin = jine * 0.1); //} else if (jine> 10 & jine <= 20) // {printf ("Your reward is: %. 4f million \ n ", jiangjin = 10*0.1 + (jine-10) * 0.075); //} else if (jine> 20 & jine <= 40) // {printf ("Your reward is: %. 4f million \ n ", jiangjin = 10*0.1 + 10*0.075 + (jine-20) * 0.05); //} else if (jine> 40 & jine <= 60) // {printf ("Your reward is: %. 4f Yuan \ n ", jiangjin = 10*0.1 + 10*0.075 + 20*0.05 + (jine-40) * 0.03 ); //} else if (jine> 60 & jine <= 100) // {printf ("Your reward is: %. 4f Yuan \ n ", jiangjin = 10*0.1 + 10*0.075 + 20*0.05 + 20*0.03 + (jine-60) * 0.15 ); //} else if (jine> 100) // {printf ("Your reward is: %. 4f Yuan \ n ", jiangjin = 10*0.1 + 10*0.075 + 20*0.05 + 20*0.03 + 40*0.015 + (jine-100 )); //} // else {// printf ("You are amazing "); /// //} // else {// printf ("I am really tired "); ///} //// company employee // int jy, xl, js, sum; // printf ("Enter your work experience \ n "); // scanf ("% d", & jy); // printf ("Enter your degree \ n"); // scanf ("% d", & xl ); // printf ("enter technical qualifications \ n"); // scanf ("% d", & js); // if (jy = 0) {// printf ("fresh graduates 0 points \ n"); //} else if (jy <= 1) // {printf ("less than one year of work experience: 1 point \ n"); //} else if (jy> 1 & jy <3) // {printf ("2 points \ n"); //} else if (jy> = 3 & jy <7) // {printf ("3 points \ n"); //} else if (jy> = 7) // {printf ("4 points \ n "); ///} // else {// printf ("your input is incorrect \ n"); // switch (xl) {// case 1: // printf ("1 point \ n"); // break; // case 2: // printf ("2 points \ n"); // break; // case 3: // printf ("graduate student + 3 points \ n"); // break; // default: printf ("your input work experience is incorrect \ n"); // break; //} // switch (js) {// case 0: // printf ("unqualified 0 points \ n"); // break; // case 1: // printf ("Beginner 1 point \ n"); // break; // case 2: // printf ("Intermediate 2 points \ n"); // break; // case 3: // printf ("advanced 3 points \ n "); // break; // default: // printf ("your input qualifications are incorrect \ n"); // break; ///} // printf ("top salary: % d \ n", sum = jy + xl + js ); ///// bank deposit // double m; //// char hq; // int dq; // printf ("Enter your deposit amount \ n"); // scanf ("% lf", & m ); // printf ("Enter your deposit type, please press d (regular) or h (current) \ n"); // scanf ("% c", & hq ); //// if (hq = 'H' | hq = 'H') {// printf ("Your money is: %. 6f \ n ", m * 0.0035); // else if (hq = 'D' | hq = 'D ') /// {/// printf ("Enter your choice (1-> full storage, 2-> zero storage, 3-> set the active ratio \ n "); // scanf ("% d", & dq); // switch (dq) {// case 1: // printf ("the total fee is %. 6f \ n ", m * 0.0325); // break; // case 2: // printf (" the sum of 0 s is %. 6f \ n ", m * 0.0285); // break; // case 3: // printf (" the sum of money is %. 6f \ n ", m x 0.0325*0.6); // break; // default: // break; //} // else {// printf ("your input is incorrect "); ///} // seldom go to the park // int m = 120, zl; // float sg; // printf ("select a type (1-> old man, 2-student, 3-officer, 4-child) \ n "); // scanf (" % d ", & zl ); // if (zl = 1) // {// printf ("required amount: % d \ n", m * 0 ); //} // else if (zl = 2 | zl = 3) // {// printf ("required amount: % d \ n ", m/2); //} else if (zl = 4) // {// printf ("Enter the height of the ticket (meter) \ n "); // scanf ("% f", & sg); // if (sg <1.20) // {// printf ("no ticket purchased \ n "); //} else if (sg> = 1.20) & (sg <= 1.50) // {// printf ("buy children's ticket %. f $ \ n ", m * 0.3); // else {// printf (" buy adult ticket \ n "); ///} //} else // {// printf ("your input is incorrect \ n ");////}//