C语言基础应用处理学生打分 计算时间 最少硬币问题详细过程
第一题: 最少硬币问题(简单版)
? 假设有三种面值的硬币,分别为10、5、1。接收一个整数作为金额数,计算要达到该金额数,每个面值的硬币最少需要多少枚。
输出结果演示:
? 参考答案:
#include <stdio.h> typedef struct StructrueMoneyBox { int n10; int n5; int n1; } MoneyBox; int main(void) { MoneyBox change = {0, 0, 0}; int face_value[4] = {10, 5, 1}; int money = 0; int i = 0; printf("请输入金额: "); scanf("%d", &money); do { if (money < face_value[i]) { i++; } switch (i) { case 0: change.n10 = money / face_value[i]; break; case 1: change.n5 = money / face_value[i]; break; case 2: change.n1 = money / face_value[i]; break; } money = money % face_value[i]; } while (money > 0); printf("10: %d\n", change.n10); printf("5: %d\n", change.n5); printf("1: %d\n", change.n1); return 0; }
? 运行结果:
第二题:计算已经过去了多久
编写一个秒表程序来计算已经过去了多长时间。
利用下列结构体实现:
并要求使用下面两个变量来解决问题:
当程序运行时,取当前时间并保存到 previtimePtr 变量中。
此后,程序将无限地接受命令,直到用户输入“quit” 程序才会停止。
如果用户输入“check”,则输出存储的上一个时间与当前时间的差。
(其他命令不采取任何操作)
提示:取现行时间的方法
#include <stdio.h> #include <time.h> int main(void) { time_t timer; struct tm *t; timer = time(NULL); t = localtime(&timer); return 0; }
输出结果演示:
? 参考答案:
#include <stdio.h> #include <time.h> #include <string.h> #include <stdlib.h> typedef struct{ int hours; int minutes; int seconds; }Time; int main(void){ Time* prevTimePtr; Time currTime; time_t timer; struct tm *t; int i = 1, a, b, c; char buf[80]; timer = time(NULL); t = localtime(&timer); prevTimePtr = (Time*)malloc(sizeof(Time)); prevTimePtr->hours = t->tm_hour; prevTimePtr->minutes = t->tm_min; prevTimePtr->seconds = t->tm_sec; while(1){ printf("system> "); fgets(buf, 80, stdin); if(!strcmp(buf, "quit\n")) break; if(!strcmp(buf, "check\n")){ timer = time(NULL); t = localtime(&timer); currTime.hours = t->tm_hour; currTime.minutes = t->tm_min; currTime.seconds = t->tm_sec; printf("\n\tCheck Point #%02d\n", i++); printf("\tCurrent Time = %02d : %02d : %02d\n", currTime.hours, currTime.minutes, currTime.seconds); printf("\tPrevious Time = %02d : %02d : %02d\n", prevTimePtr->hours, prevTimePtr->minutes, prevTimePtr->seconds); c = currTime.seconds - prevTimePtr->seconds; b = currTime.minutes - prevTimePtr->minutes; a = currTime.hours - prevTimePtr->hours; if(c < 0){ c+=60; b--; } if(b < 0){ b+=60; a--; } printf("\tElasped Time = %02d : %02d : %02d\n\n", a,b,c); *prevTimePtr = currTime; } } return 0; }
? 运行结果:
第三题:学生成绩自动打分
? 编写一个管理学生成绩,并带有计算学生成绩功能的小程序。
使用下面的结构来存储学生信息:
例如,上述结构中一个学生的值如下:
Grades student1 = {2601053, "Natalie Lewis", {30.5, 65.9, 69.6}};
程序启动时,在文本文件(“input.txt”)中读取信息。(这里请手动创建该文件!)
文件内容如下:
26
2601053 / Natalie Lewis / 30.5 / 65.9 / 69.6
2026018 / Chloe Christian / 54.1 / 43.4 / 35.4
2016317 / Emolys Evans / 31.6 / 20.4 / 26.3
2961329 / Sophia Allen / 63.5 / 37.9 / 56.8
2016787 / Robert Melton / 44.1 / 54.2 / 32.7
2011661 / Siaomos Barton / 92.2 / 15.4 / 33.7
8166559 / Sebastian Henderson / 55.1 / 38.2 / 0.9
2061185 / Richard Cerney / 63.6 / 98.6 / 97.0
2017454 / Elizabeth Calvin / 7.4 / 0.0 / 26.4
2026196 / Madison Frost / 49.3 / 64.3 / 73.3
2015758 / Emily Stevgenson / 51.6 / 89.2 / 34.0
2016776 / Navy Taylor / 8.6 / 36.4 / 52.3
2062103 / Vincent Newton / 38.7 / 79.0 / 24.0
2501762 / Owen Ingram / 40.6 / 85.1 / 91.1
2042142 / Olyen Massey / 72.1 / 62.0 / 97.3
2027039 / Emma Thomas / 30.1 / 25.1 / 27.3
2051341 / Peter Pitts / 47.9 / 71.8 / 74.9
2071368 / Xygret Latimer / 67.2 / 9.7 / 79.1
2023762 / Michael Grahan / 6.4 / 29.0 / 17.5
2024545 / Mandon Austin / 98.8 / 28.5 / 48.9
2091176 / Violet Smith / 4.8 / 93.9 / 3.9
2802841 / Samuel Davis / 95.6 / 54.2 / 31.8
2027062 / Sam Mackey / 83.6 / 26.1 / 97.5
2061555 / Miguel Parr / 77.2 / 88.1 / 99.5
2028836 / Oscar Hamersley / 67.7 / 43.4 / 91.7
2026582 / MeanSon King / 97.2 / 88.3 / 100.0
文本的第一行显示了学生人数 n
从第二行开始,按照“id/name/mid/final/proj”的顺序给出了学生的信息。
通过根据所有学生的成绩计算排名来确定学生的最终成绩:
① 总分评判规则: total_point = mid * 0.3 + final * 0.3 + prog * 0
② 评分评判规则: 成绩前 30% 为 A,前 70% 为 B,其余为 C
③ 总分小于 30(total_point < 30) 的学生,无视排名给 F。
输入的成绩范围限制在 0~100分,学生姓名长度限制在40个字符以内。
仅对给定的文本文件内的学生进行评分,输出文件的位置随意。
输出效果演示:
? 参考答案:
#include <stdio.h> #include <stdlib.h> #include <string.h> typedef struct{ float mid; float final; float proj; }Points; typedef struct{ int studentId; char name[40]; Points subject; char grade[3]; float total_point; }Grades; int main(void){ int cnt, i, j, A_temp, B_temp; float a_grade, b_grade; char name_temp[30]; Grades* grade; Grades gtemp; FILE *fp = fopen("input.txt", "r"); if(fp == NULL){ printf("未找到文件!\n"); return 1; } fscanf(fp, "%d", &cnt); A_temp = cnt * 0.3; B_temp = cnt * 0.7; grade = (Grades*)malloc(sizeof(Grades) * cnt); for(i = 0; i < cnt; i++){ fscanf(fp, "%d / %s %s / %f / %f / %f\n", &grade[i].studentId, grade[i].name, name_temp, &((grade[i].subject).mid), &(grade[i].subject).final, &(grade[i].subject).proj); strcat(grade[i].name, " "); strcat(grade[i].name, name_temp); grade[i].total_point = (grade[i].subject).mid * 0.3 + (grade[i].subject).final * 0.3 + (grade[i].subject).proj * 0.4; } for(i = 0; i < cnt - 1; i++){ for(j = 0; j < cnt - i - 1; j++){ if(grade[j].total_point < grade[j + 1].total_point){ gtemp = grade[j]; grade[j] = grade[j + 1]; grade[j + 1] = gtemp; } } } a_grade = grade[A_temp].total_point; b_grade = grade[B_temp].total_point; printf("Cut off for A grade: %f (rank %d)\n", a_grade, A_temp); printf("Cut off for B grade: %f (rank %d)\n", b_grade, B_temp); for(i = 0; i < cnt; i++){ if(grade[i].total_point < 30){ strcpy(grade[i].grade, "F"); } else if(a_grade <= grade[i].total_point){ strcpy(grade[i].grade, "A"); } else if(b_grade <= grade[i].total_point && grade[i].total_point < a_grade){ strcpy(grade[i].grade, "B"); } else if(grade[i].total_point < b_grade){ strcpy(grade[i].grade, "C"); } } printf("\n-- Student List --\n"); for(i = 0; i < cnt; i++){ printf(" Id : %d\n", grade[i].studentId); printf(" Name : %s\n", grade[i].name); printf(" Grade(mid) : %.02f\n", (grade[i].subject).mid); printf(" Grade(final) : %.02f\n", (grade[i].subject).final); printf(" Grade(project) : %.02f\n", (grade[i].subject).proj); printf(" Grade : %s (%.02f, rank %d)\n", grade[i].grade, grade[i].total_point, i + 1); printf("\n"); } return 0; }
? 运行结果:
Cut off for A grade: 65.870003 (rank 7)
Cut off for B grade: 42.570000 (rank 18)-- Student List --
Id : 2026582
Name : MeanSon King
Grade(mid) : 97.20
Grade(final) : 88.30
Grade(project) : 100.00
Grade : A (95.65, rank 1)Id : 2061555
Name : Miguel Parr
Grade(mid) : 77.20
Grade(final) : 88.10
Grade(project) : 99.50
Grade : A (89.39, rank 2)Id : 2061185
Name : Richard Cerney
Grade(mid) : 63.60
Grade(final) : 98.60
Grade(project) : 97.00
Grade : A (87.46, rank 3)Id : 2042142
Name : Olyen Massey
Grade(mid) : 72.10
Grade(final) : 62.00
Grade(project) : 97.30
Grade : A (79.15, rank 4)Id : 2501762
Name : Owen Ingram
Grade(mid) : 40.60
Grade(final) : 85.10
Grade(project) : 91.10
Grade : A (74.15, rank 5)Id : 2027062
Name : Sam Mackey
Grade(mid) : 83.60
Grade(final) : 26.10
Grade(project) : 97.50
Grade : A (71.91, rank 6)Id : 2028836
Name : Oscar Hamersley
Grade(mid) : 67.70
Grade(final) : 43.40
Grade(project) : 91.70
Grade : A (70.01, rank 7)Id : 2051341
Name : Peter Pitts
Grade(mid) : 47.90
Grade(final) : 71.80
Grade(project) : 74.90
Grade : A (65.87, rank 8)Id : 2026196
Name : Madison Frost
Grade(mid) : 49.30
Grade(final) : 64.30
Grade(project) : 73.30
Grade : B (63.40, rank 9)Id : 2024545
Name : Mandon Austin
Grade(mid) : 98.80
Grade(final) : 28.50
Grade(project) : 48.90
Grade : B (57.75, rank 10)Id : 2802841
Name : Samuel Davis
Grade(mid) : 95.60
Grade(final) : 54.20
Grade(project) : 31.80
Grade : B (57.66, rank 11)Id : 2601053
Name : Natalie Lewis
Grade(mid) : 30.50
Grade(final) : 65.90
Grade(project) : 69.60
Grade : B (56.76, rank 12)Id : 2015758
Name : Emily Stevgenson
Grade(mid) : 51.60
Grade(final) : 89.20
Grade(project) : 34.00
Grade : B (55.84, rank 13)Id : 2071368
Name : Xygret Latimer
Grade(mid) : 67.20
Grade(final) : 9.70
Grade(project) : 79.10
Grade : B (54.71, rank 14)Id : 2961329
Name : Sophia Allen
Grade(mid) : 63.50
Grade(final) : 37.90
Grade(project) : 56.80
Grade : B (53.14, rank 15)Id : 2011661
Name : Siaomos Barton
Grade(mid) : 92.20
Grade(final) : 15.40
Grade(project) : 33.70
Grade : B (45.76, rank 16)Id : 2062103
Name : Vincent Newton
Grade(mid) : 38.70
Grade(final) : 79.00
Grade(project) : 24.00
Grade : B (44.91, rank 17)Id : 2026018
Name : Chloe Christian
Grade(mid) : 54.10
Grade(final) : 43.40
Grade(project) : 35.40
Grade : B (43.41, rank 18)Id : 2016787
Name : Robert Melton
Grade(mid) : 44.10
Grade(final) : 54.20
Grade(project) : 32.70
Grade : B (42.57, rank 19)Id : 2016776
Name : Navy Taylor
Grade(mid) : 8.60
Grade(final) : 36.40
Grade(project) : 52.30
Grade : C (34.42, rank 20)Id : 2091176
Name : Violet Smith
Grade(mid) : 4.80
Grade(final) : 93.90
Grade(project) : 3.90
Grade : C (31.17, rank 21)Id : 8166559
Name : Sebastian Henderson
Grade(mid) : 55.10
Grade(final) : 38.20
Grade(project) : 0.90
Grade : F (28.35, rank 22)Id : 2027039
Name : Emma Thomas
Grade(mid) : 30.10
Grade(final) : 25.10
Grade(project) : 27.30
Grade : F (27.48, rank 23)Id : 2016317
Name : Emolys Evans
Grade(mid) : 31.60
Grade(final) : 20.40
Grade(project) : 26.30
Grade : F (26.12, rank 24)Id : 2023762
Name : Michael Grahan
Grade(mid) : 6.40
Grade(final) : 29.00
Grade(project) : 17.50
Grade : F (17.62, rank 25)Id : 2017454
Name : Elizabeth Calvin
Grade(mid) : 7.40
Grade(final) : 0.00
Grade(project) : 26.40
Grade : F (12.78, rank 26)
参考资料:
Microsoft. MSDN(Microsoft Developer Network)[EB/OL]. []. .
百度百科[EB/OL]. []. https://baike.baidu.com/.
? 笔者:王亦优
? 更新: 2021.12.14
? 勘误: 无
? 声明: 由于作者水平有限,本文有错误和不准确之处在所难免,本人也很想知道这些错误,恳望读者批评指正
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