C語言程序設(shè)計課件(蘇小紅)第3章

1、哈爾濱工業(yè)大學(xué)哈爾濱工業(yè)大學(xué)計算機(jī)科學(xué)與技術(shù)學(xué)院計算機(jī)科學(xué)與技術(shù)學(xué)院蘇小紅蘇小紅2022-4-292/512022-4-293/512022-4-294/51Example:2022-4-295/512022-4-296/51Example:浮點(diǎn)數(shù)除法浮點(diǎn)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 integers2022-4-297/51Example:2022-4-298/51Example:2022-4-299/512022-4-2910/51Example:1152101r

2、emainderresult2022-4-2911/51Example:-115-2-10-1remainderresult2022-4-2912/51Example:11-5-210 1remainderresult2022-4-2913/51Example:2022-4-2914/512022-4-2915/512022-4-2916/51Example: 2022-4-2917/51Example:2022-4-2918/51Example:2022-4-2919/512022-4-2920/512022-4-2921/51關(guān)鍵是如何分離個位、關(guān)鍵是如何分離個位、十位和百十位和百位數(shù)字？

3、位數(shù)字？2022-4-2922/51#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);2022-4-2923/512022-4-2924/512022-4-2925/51Example:num = num + 5;num1520Example:num += 5;2022-4-2926/51已知已知 in

4、t 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 = 02022-4-2927/51OperationExamples of expressionDescription+=num += 5;num = num + 5;-=num -= 5;num = num 5;*=num *= 5;num = num * 5;/=nu

5、m /= 5;num = num / 5;%=num %= 5;num = num % 5;2022-4-2928/512022-4-2929/512022-4-2930/51Example:j = +i - 2i5similar to j? 462022-4-2931/51Example:j = i+ - 2i5similar to j? 362022-4-2932/51int a=3;printf(%d, -a+);a3similar to 42022-4-2933/512022-4-2934/51circumference = 33.300854area = 88.247263#incl

6、ude main() double r = 5.3; printf(circumference = %fn, 2*3.14159*r); printf(area = %fn, 3.14159*r*r);2022-4-2935/51#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 = 33.300854 area =

7、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) 2022-4-2936/512022-4-2937/512022-4-2938/51#include main() double r; printf(Input r:); scanf(%lf, &r); printf(circumference = %fn, 2*PI*r); printf(area = %fn, PI*r*r);2022-4-2939/51#include #define PI 3.14159;#define R 5.3;main()printf(area =

8、%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;);2022-4-2940/51#include main() const double PI = 3.14159; double r; printf(Input r:); scanf(%lf, &r); printf(circumference = %fn, 2

9、*PI*r); printf(area = %fn, PI*r*r);2022-4-2941/51doublefloatlongunsignedintchar，short低高2022-4-2942/512022-4-2943/512022-4-2944/51Example: int x = 10;float y;y = (float)x;x10y?10.0000002022-4-2945/51Example: 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(diǎn)數(shù)還是整數(shù)，不是浮點(diǎn)數(shù)2022-4-2946/51Example: int total, number;float average;average = (float)total / number;total15number2average?7.5000002022-4-29