第4章_程序控制結(jié)構(gòu)-1

1、1哈爾濱工業(yè)大學(xué)哈爾濱工業(yè)大學(xué)計(jì)算機(jī)科學(xué)與技術(shù)學(xué)院計(jì)算機(jī)科學(xué)與技術(shù)學(xué)院蘇小紅蘇小紅2021-10-182/612021-10-183/612021-10-184/612021-10-185/612021-10-186/612021-10-187/612021-10-188/612021-10-189/612021-10-1810/612021-10-1811/612021-10-1812/612021-10-1813/61Start/EndProcessInput/OutputTestConnectorFlow of activities2021-10-1814/612021-10-1815/

2、612021-10-1816/61 2021-10-1817/61 2021-10-1818/61main() scanf(%d, &quantity); scanf(%d, &pricePerkg); price = quantity*pricePerkg; printf(%d, price); 2021-10-1819/61main() int quantity,price_per_kg,price; scanf(%d, &quantity); scanf(%d, &pricePerkg); price = quantity*pricePerkg; printf(%d, price); 2

3、021-10-1820/61main() int quantity,price_per_kg,price; scanf(%d, &quantity); scanf(%d, &pricePerkg); price = quantity*pricePerkg; printf(%d, price); 2021-10-1821/612021-10-1822/61NS圖2021-10-1823/61計(jì)算兩個(gè)數(shù)中的最小者計(jì)算兩個(gè)數(shù)中的最小者. 2021-10-1824/61ABNYNS圖圖傳統(tǒng)流程圖傳統(tǒng)流程圖2021-10-1825/61 2021-10-1826/61 2021-10-1827/61ma

4、in() int num1, num2, min; scanf(%d%d, &num1, &num2); if (num1 num2) min =num1; else min = num2; printf(%d, min); 2021-10-1828/612021-10-1829/61step aif startstep mstep nend_ifstep b2021-10-1830/61Syntax:復(fù)合語句復(fù)合語句compound statement被當(dāng)作一條語句看待被當(dāng)作一條語句看待2021-10-1831/61Syntax:2021-10-1832/61Single Selection

5、 Pseudocode :if startstep 1step 2step kend_if Statement:if (expression) statement 1statement 2statement k2021-10-1833/61main() int num1, num2, min; printf(“Input 2 numbers: “); scanf(“%d%d”, &num1, &num2); min = num1; if (num1 num2)min = num2; printf(“Smallest: %dn”, min);Input 2 numbers: _num2?num1

6、?min?Input 2 numbers: 20 15_20152015Input 2 numbers: 20 15Smallest: 15_2021-10-1834/61Example:main() int mark;scanf(“%d”, &mark);if (mark = 60)printf(“Passn”);printf(“Your mark is %d”, mark);2021-10-1835/61Example:main() int mark;scanf(“%d”, &mark);if (mark = 60)printf(“Passn”);printf(“Your mark is

7、%d”, mark);2021-10-1836/61Step aif startStep mStep nend_ifelse startStep xStep yend_elseStep z2021-10-1837/61Syntax:oror2021-10-1838/61Double Selection Pseudocode:if startstep 1step kend_ifelse startstep 1step nend_else Statement:if (expression) statement 1statement kelse statement 1statement n2021-

8、10-1839/61Example:if (num1 num2)min = num1;elsemin = num2;printf(“Smallest: %dn”, min);num215num1min?_10Smallest: 10_2021-10-1840/61Example:if (num1 num2)min = num1;elsemin = num2;printf(“Smallest: %dn”, min);num215num1min?_15Smallest: 15_2021-10-1841/61if (num1 num2) min = num1;max = num2;else min

9、= num2;max = num1;printf(“Min = %d, Max = %dn”, min, max);num2125num1700min?_max?Min = 125, Max = 700_1257002021-10-1842/61if (num1 num2)min = num1;elsemin = num2;printf(“Smallest: %dn”, min);min = num1 num2 num1 num2;printf(“Smallest: %dn”, min);2021-10-1843/61step aif (expression) step mstep nstep

10、 b2021-10-1844/61step aif startstep mstep nend_ifstep bstep aif (expression) step mstep nelse step xstep ystep bGuesshow does multiple selection look like ?2021-10-1845/61Step a (expression1)Step m (expression2) Step n Step z2021-10-1846/61Step a(expression1) Step m (expression2) Step n Step x Step

11、z2021-10-1847/612021-10-1848/61當(dāng)當(dāng)t 18時(shí)，為低體重；時(shí)，為低體重；當(dāng)當(dāng)18 t 25時(shí)，為正常體重；時(shí)，為正常體重；當(dāng)當(dāng)25 t 27時(shí)，為超重體重；時(shí)，為超重體重；當(dāng)當(dāng)t 27時(shí)，為肥胖。時(shí)，為肥胖。2021-10-1849/61當(dāng)當(dāng)t 18時(shí)，為低體重；時(shí)，為低體重；當(dāng)當(dāng)18 t 25時(shí)，為正常體重；時(shí)，為正常體重；當(dāng)當(dāng)25 t 27時(shí)，為超重體重；時(shí)，為超重體重；當(dāng)當(dāng)t 27時(shí)，為肥胖。時(shí)，為肥胖。2021-10-1850/61The structure is similar to multiple selection (flowchart)2021-

12、10-1851/61Important Rule !2021-10-1852/61Example: switch (month) case 1:printf(“Januaryn”);break;case 2:printf(“Februaryn”);break;case 3:printf(“Marchn”);break;default:printf(“Othersn”);break; printf(“End”);January_JanuaryEnd _2021-10-1853/61Example: switch (month) case 1:printf(“Januaryn”);break;ca

13、se 2:printf(“Februaryn”);break;case 3:printf(“Marchn”);break;default:printf(“Othersn”);break; printf(“End”);March_MarchEnd _2021-10-1854/61Example: switch (month) case 1:printf(“Januaryn”);break;case 2:printf(“Februaryn”);break;case 3:printf(“Marchn”);break;default:printf(“Othersn”);break; printf(“E

14、nd”);2021-10-1855/61Example: switch (month) case 1:printf(“Januaryn”);break;case 2:printf(“Februaryn”);case 3:printf(“Marchn”);break;default:printf(“Othersn”);break; printf(“End”);2021-10-1856/61Example: switch (month) case 1:printf(“Januaryn”);break;case 2:printf(“Februaryn”);case 3:printf(“Marchn”);break;default:printf(“Othersn”);break; printf(“End”);February_ March _ End _2021-10-1857/61Example: switch (month) case 1:printf(“Januaryn”);break;case 2:printf(“Februaryn”);case 3:printf(“Marchn”);br