c++钱能第一版课后习题答案.pdfVIP

（二） 2.1 #includeiostream.h voidmain() { //本题原考虑在16位机器上实验目前多为32位机器，故已过时。 inta=42486; coutoctaendl he aendl; unsignedb=42486; coutdec(signed)bendl; } 2.2 #includeiostream.h #includeiomanip.h constdoublepi=3.1415926; voidmain() { doubleradius1,radius2; coutpleaseinputtwonumbers:\n; cinradius1radius2; coutsetw(10)pisetw(10)radius1 setw(10)(pi*radius1*radius1)endl setw(10)pisetw(10)radius2 setw(10)(pi*radius2*radius2)endl; } 2.3 #includeiostream.h #includeiomanip.h constdoublee=2.718281828; voidmain() { coutsetprecision(10)eendl setiosflags(ios::fixed)setprecision(8)eendl setiosflags(ios::scientific)eendl; } 2.4 #includeiostream.h voidmain() { cout\Howmanystudentshere?\\n \500\\n; } 2.5 #includeiostream.h voidmain() { coutsizeofchar sizeof(char)byte\n sizeofunsignedchar sizeof(unsignedchar)byte\n sizeofsignedchar sizeof(signedchar)byte\n sizeofint sizeof(int)byte\n sizeofunsigned sizeof(unsigned)byte\n sizeofsigned sizeof(signed)byte\n sizeofshort sizeof(short)byte\n sizeofunsignedshortsizeof(unsignedshort)byte\n sizeoflong sizeof(long)byte\n sizeofsignedlong sizeof(signedlong)byte\n sizeofunsignedlong sizeof(unsignedlong)byte\n sizeoffloat sizeof(float)byte\n sizeofdouble sizeof(double)byte\n sizeoflongdouble sizeof(longdouble)byte\n; } 2.6 1) pleaseinput3sidesofonetriangle: 6,6,8 a= 6.00,b= 6.00,c= 8.00 areaoftriangleis 17.88854 2) 该程序计算三角形的面积 前后分为三部分：输入，处理，输出。 3) //#includestdio.h #includeiostream.h #includeiomanip.h #includemath.h voidmain() { floata,b,c,s,area; //printf(pleaseinpu