C語言程序設(shè)計課件3

1、中國石油大學(xué)中國石油大學(xué)計算機(jī)與通信工程學(xué)院計算機(jī)與通信工程學(xué)院于廣斌于廣斌2022-2-52/512022-2-53/512022-2-54/51Example:2022-2-55/512022-2-56/51Example:浮點數(shù)除法浮點數(shù)除法(Floating Division) or or both are floats整數(shù)除法整數(shù)除法(Integer Division) and are integers2022-2-57/51Example:2022-2-58/51Example:2022-2-59/512022-2-510/51Example:1152101remainderres

2、ultInteger Division2022-2-511/51Example:-115-2-10-1remainderresultInteger Division2022-2-512/51Example:11-5-210 1remainderresultInteger Division2022-2-513/51Example:2022-2-514/512022-2-515/512022-2-516/51Example: 2022-2-517/51Example:2022-2-518/51Example:2022-2-519/512022-2-520/512022-2-521/512022-2

3、-522/51關(guān)鍵是如何分離個位、十位和百位數(shù)字？關(guān)鍵是如何分離個位、十位和百位數(shù)字？2022-2-523/51#include main() int x = 153, b0, b1, b2, sum; b2 = x / 100; b1 = (x - b2 * 100) / 10; b0 = x % 10; sum = b2 + b1 + b0; printf(b2=%d, b1=%d, b0=%d, sum=%dn, b2, b1, b0, sum);2022-2-524/512022-2-525/51Example:num = num + 5;num1520Example:num += 5

4、;2022-2-526/51已知已知 int a = 3;執(zhí)行執(zhí)行 a += a -= a * a 后，變量后，變量a的值？的值？ a += a -= a * a a += a -= 9 a += -6 a = -12執(zhí)行執(zhí)行 a += a -= a *= a 后，變量后，變量a的值？的值？ a += a -= a *= a a += a -= 9 a += 0 a = 02022-2-527/51OperationExamples of expressionDescription+=num += 5;num = num + 5;-=num -= 5;num = num 5;*=num *=

5、5;num = num * 5;/=num /= 5;num = num / 5;%=num %= 5;num = num % 5;2022-2-528/512022-2-529/512022-2-530/51Example:j = +i - 2i5similar to j? 462022-2-531/51Example:j = i+ - 2i5similar to j? 362022-2-532/51int a=3;printf(%d, -a+);a3similar to 42022-2-533/512022-2-534/51circumference = 33.300854area = 8

6、8.247263#include main() double r = 5.3; printf(circumference = %fn, 2*3.14159*r); printf(area = %fn, 3.14159*r*r);2022-2-535/51#include main() double r; printf(Input r:); scanf(%lf, &r); printf(circumference = %fn, 2*3.14159*r); printf(area = %fn, 3.14159*r*r); Input r: 5.3 circumference = 33.30

7、0854 area = 88.247263在程序中直接使用的常數(shù)稱在程序中直接使用的常數(shù)稱為幻數(shù)為幻數(shù)(Magic Number) 2022-2-536/512022-2-537/512022-2-538/51#include #define PI 3.14159main() double r; printf(Input r:); scanf(%lf, &r); printf(circumference = %fn, 2*PI*r); printf(area = %fn, PI*r*r);2022-2-539/51#include #define PI 3.14159;#define

8、R 5.3;main()printf(area = %fn, PI * R * R);printf(circumference = %fn, 2 * PI * R);相當(dāng)于執(zhí)行相當(dāng)于執(zhí)行#include main()printf(area = %fn, 3.14159;*5.3;*5.3;);printf(circumference = %fn, 2*3.14159;*5.3;);2022-2-540/51#include main() const double PI = 3.14159; double r; printf(Input r:); scanf(%lf, &r); prin

9、tf(circumference = %fn, 2*PI*r); printf(area = %fn, PI*r*r);2022-2-541/51u 強(qiáng)制類型轉(zhuǎn)換運(yùn)算符強(qiáng)制類型轉(zhuǎn)換運(yùn)算符u 表達(dá)式與賦值中的自動類型轉(zhuǎn)換表達(dá)式與賦值中的自動類型轉(zhuǎn)換2022-2-542/51doublefloatlongunsignedintchar，short低高2022-2-543/512022-2-544/512022-2-545/51Example: int x = 10;float y;y = (float)x;x10y?10.0000002022-2-546/51Example: int total, number;float average;average = total / number;total15number2average?7.000000兩個整數(shù)運(yùn)算的結(jié)果兩個整數(shù)運(yùn)算的結(jié)果還是整數(shù)，不是浮點數(shù)還是整數(shù)，不是浮點數(shù)2022-2-547/51Example: int total, number;float average;average = (float)total / number;total15number2aver