From b4c35a325c37ddcf91101d6ae4ac30d961e62b62 Mon Sep 17 00:00:00 2001 From: unlockable Date: Fri, 11 Nov 2022 23:49:31 +0800 Subject: [PATCH] =?UTF-8?q?Lesson=209=E3=80=82?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- 09/Exercise01.c | 40 ++++++++++++++++++++++ 09/Exercise02.c | 91 +++++++++++++++++++++++++++++++++++++++++++++++++ 09/Optional01.c | 41 ++++++++++++++++++++++ 09/Optional02.c | 33 ++++++++++++++++++ 09/Optional03.c | 30 ++++++++++++++++ 5 files changed, 235 insertions(+) create mode 100644 09/Exercise01.c create mode 100644 09/Exercise02.c create mode 100644 09/Optional01.c create mode 100644 09/Optional02.c create mode 100644 09/Optional03.c diff --git a/09/Exercise01.c b/09/Exercise01.c new file mode 100644 index 0000000..43130ba --- /dev/null +++ b/09/Exercise01.c @@ -0,0 +1,40 @@ +#include +#include + +int findMaxFirst(int sheep[]) { + int max = 0; + int i = 0; + max = sheep[0]; + for (i = 1; i < 100; i++) { + if (sheep[i] > max) { + max = sheep[i]; + } + } + return max; +} + +int findMaxRecursive(int sheep[], int start, int prevMax) { + if (start == 100) { + return prevMax; + } + else { + return findMaxRecursive(sheep, start+1, sheep[start] > prevMax? sheep[start]:prevMax); + } +} + +int main() { + int sheep[100] = {0}; + int i = 0; + int max1 = 0, max2 = 0; + for (i = 0; i < 100; i++) { + sheep[i] = rand() % 1000; + } + // for (i = 0; i < 100; i++) { + // printf("%d\n", sheep[i]); + // } + max1 = findMaxFirst(sheep); + max2 = findMaxRecursive(sheep, 0, 0); + printf("By first method, the max is %d\n", max1); + printf("By second method, the max is %d", max2); + return 0; +} \ No newline at end of file diff --git a/09/Exercise02.c b/09/Exercise02.c new file mode 100644 index 0000000..9c698ed --- /dev/null +++ b/09/Exercise02.c @@ -0,0 +1,91 @@ +#include +#include + +double matA[4][4] = { + {1.1161, 0.1254, 0.1397, 0.1490}, + {0.1582, 1.1675, 0.1768, 0.1871}, + {0.2368, 0.2471, 0.2568, 1.2671}, + {0.1968, 0.2071, 1.2168 ,0.2271} +}; + +double matB[4] = { + 1.5471, 1.6471, 1.8471, 1.7571 +}; + +void rowManipulation(int originRow, double coefficent, int rowBeingAdded) { + int col = 0; + for (col = 0; col < 4; col++) { + matA[rowBeingAdded][col] += matA[originRow][col] * coefficent; + } + matB[rowBeingAdded] += matB[originRow] * coefficent; +} + +void timesOfRow(int rowCount, double time) { + int col = 0; + for (col = 0; col < 4; col++) { + matA[rowCount][col] *= time; + } + matB[rowCount] *= time; +} + +int findNoneZeroItem(int startRowIndex, int columnIndex) { + bool found = false; + int pos = startRowIndex; + for (pos = startRowIndex; pos < 4; pos++) { + if (matA[pos][columnIndex] != 0) { + return pos; + } + } + return -1; +} + +void swapRow(int firstRowIndex, int secondRowIndex) { + double temp = 0; + int i = 0; + for (i = 0; i < 4; i++) { + temp = matA[firstRowIndex][i]; + matA[firstRowIndex][i] = matA[secondRowIndex][i]; + matA[secondRowIndex][i] = temp; + } + temp = matB[firstRowIndex]; + matB[firstRowIndex] = matB[secondRowIndex]; + matB[secondRowIndex] = temp; +} + +void printOut() { + int i = 0, j = 0; + for (i = 0; i < 4; i++) { + for (j = 0; j < 4; j++) { + printf("%lf\t", matA[i][j]); + } + printf("%lf", matB[i]); + printf("\n"); + } +} + +int main() { + int x[4] = {0}; + int column = 0, row = 0; + int tempRow = 0; + int noneZeroRow = 0; + for (column = 0; column < 4; column++) { + noneZeroRow = findNoneZeroItem(row, column); + if (noneZeroRow == -1) { + continue; + } + else { + swapRow(row, noneZeroRow); + timesOfRow(row, 1.0/matA[row][column]); + for (tempRow = 0; tempRow < 4; tempRow++) { + if (tempRow != row) + rowManipulation(row, -matA[tempRow][column], tempRow); + } + row++; + } + + } + for (row = 0; row < 4; row++) { + printf("x(%d) = %lf\n", row+1, matB[row]); + } + return 0; +} \ No newline at end of file diff --git a/09/Optional01.c b/09/Optional01.c new file mode 100644 index 0000000..8dfc06d --- /dev/null +++ b/09/Optional01.c @@ -0,0 +1,41 @@ +#include +#include + +int history[1000] = {0}; +int nextIndex = 0; + +int inHistory(int num) { + int i = 0; + for (i = 0; i < nextIndex; i++) { + if (history[i] == num) { + return true; + } + } + return false; +} + +int main() { + int input = 0; + int sum = 0; + int singleDigit = 0; + scanf("%d", &input); + do { + sum = 0; + while (input > 0) { + singleDigit = input % 10; + sum += singleDigit * singleDigit; + input /= 10; + } + input = sum; + if (inHistory(sum)) { + history[nextIndex] = 0; + } + else { + history[nextIndex] = sum; + } + nextIndex++; + } + while (history[nextIndex-1] > 1); + printf("%d\n", history[nextIndex-1]); + return 0; +} \ No newline at end of file diff --git a/09/Optional02.c b/09/Optional02.c new file mode 100644 index 0000000..0b7597c --- /dev/null +++ b/09/Optional02.c @@ -0,0 +1,33 @@ +#include + +void fun(int a[], int n, int flag) { + int t, i, j, k; + for (i = 0; i < n - 1; i++) { + k = i; + for (j = i + 1; j < n; j++) { + if (flag ? a[k] > a[j]: a[k] < a[j]) { + k = j; + } + if (k != i) { + t = a[k]; + a[k] = a[i]; + a[i] = t; + // Swap a[k] and a[i] + } + } + } +} + +int main() { + int c[10] = {8, 6, 7, 10, 9, 3, 5, 2, 4, 1}, i; + fun(c, 5, 0); + //fun(c + 5, 5, 1); + for (i = 0; i < 10; i++) { + printf("%d, ", c[i]); + } + + //9, 10, 8, 7, 6, 1, 2, 3, 4, 5, + //一个莫名其妙的排序，它不一定能给出正确的顺序。 + //老师出这个题的意义可能只是想强调c是一个指针，加5就代表着c[5]的地址？ + return 0; +} \ No newline at end of file diff --git a/09/Optional03.c b/09/Optional03.c new file mode 100644 index 0000000..e03d591 --- /dev/null +++ b/09/Optional03.c @@ -0,0 +1,30 @@ +#include + +int main() { + char idCardNo[18] = {0}; + int i = 0, sum = 0; + int temp = 0; + char checkSum = 0; + int weigh[17] = {7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2}; + for (i = 0; i < 18; i++) { + idCardNo[i] = getchar(); + } + for (i = 0; i < 17; i++) { + temp = ((idCardNo[i] - '0')*weigh[i]) % 11; + sum += ((idCardNo[i] - '0')*weigh[i]) % 11; + } + checkSum = (12 - (sum % 11)) % 11; + if (checkSum == 10) { + checkSum = 'X'; + } + else { + checkSum += '0'; + } + if (checkSum == idCardNo[17]) { + printf("合法\n"); + } + else { + printf("非法，正确校验位是%c", checkSum); + } + return 0; +} \ No newline at end of file