c/c++练习002

/*已知数据文件IN.DAT中存有200个四位数，并已调用读函数readDat()把这些数存入数组a中，请考生编制一函数jsVal()，其功能是：如果四位数个位上的数字均是0或2或4或6或8，则统计出满足此条件的个数cnt，并把这些四位数按从大到小的顺序存入数组b中。最后main( )函数调用写函数writeDat()把结果cnt以及数组b中符合条件的四位数输出到OUT.DAT文件中。*//*随机产生200个四位数，并写入到文件(in.dat)中*/void WriteRandom(char* pFileName){if ( !pFileName ) return;//生成200个随机数int i = 0;FILE* file = fopen(pFileName, "w");if ( !file ) return;srand(time(NULL));for ( ;i < 200;++i ){int num = rand()%100 * 100 + rand()%100;if ( IsFourFigure(num) ){printf("%d/n", num);fprintf(file, "%d/n", num);}}fclose(file);}/*判断随机数是否为四位*/int IsFourFigure(int num){int i = 0;do{ num = num / 10;++i;}while( num );if ( 4 == i ){return 1;}return 0;}///////////////////////////////////////////////////////////////////////////*功能：读取数据并存储*/void ReadDataAndStor(int* nNum, char* pFileName){if ( !nNum ) return;FILE* fRead = fopen(pFileName, "r");if ( !fRead ) return;int i = 0;while ( 1 ){if ( feof( fRead ) ) return;fscanf(fRead, "%d", &nNum[i]);++i;}fclose(fRead);}/*功能：将个位上的数字为0、2、4、6、8的数按从大到小的顺序存储到数组中*/void GetDataByCondition(char* pFileName, char* pWriteFileName){int* nA = (int*)malloc(sizeof(int)* 200);memset(nA, 0, sizeof(int)* 200);int* nB = (int*)malloc(sizeof(int)* 200);memset(nB, 0, sizeof(int)* 200);ReadDataAndStor(nA, pFileName);//设置数据int i = 0;int nIndex = 0;for ( ;i < 200;++i ){if ( 0 == nA[i] % 10 || 2 == nA[i] % 10 || 4 == nA[i] % 10 || 6 == nA[i] % 10 || 8 == nA[i] % 10 ){nB[i] = nA[i];++nIndex;}}/*排序*/SortNum(nB, nIndex);/*写入文件*/WriteDataByCondition(nIndex, nB, pWriteFileName);}/*功能：将符合条件的数字总数和数字写到文件中*/void WriteDataByCondition(int nCnt, int* nNum, char* pWriteFileName){if ( !nNum ) return;FILE* file = fopen(pWriteFileName, "w");if ( !file ) return;int n = 0;for ( ;n < nCnt;++n ){fprintf(file, "%d/n", nNum[n]);}fclose(file);}/*功能：排序法*/void SortNum(int* pNum, int nLength){if ( !pNum ) return;int i = 0;int j = 0;/*交换排序*/for ( ;i < nLength;++i ){int nChangEx = 0;for ( j = i;j < nLength;++j ){if ( pNum[j] > pNum[i] ){int nTemp = pNum[j];pNum[j] = pNum[i];pNum[i] = nTemp;++nChangEx;}}if ( !nChangEx ){break;}}}