练习2-1
/* 倒计时后显示程序运行时间 */ #include <time.h> #include <stdio.h> /*--- 等待x毫秒 ---*/ int sleep(unsigned long x) { clock_t c1 = clock(), c2; do { if ((c2 = clock()) == (clock_t)-1) /* 错误 */ return 0; } while (1000.0 * (c2 - c1) / CLOCKS_PER_SEC < x); return 1; } int main(void) { int i; clock_t c; for (i = 10; i > 0; i--) { /* 倒数 */ printf("\r%2d", i); fflush(stdout); sleep(1000); /* 暂停1秒 */ } printf("\r\aFIRE!!\n"); c = clock(); printf("程序开始运行后经过了%.1f秒。经过的时钟数是:%d\n", (double)c / CLOCKS_PER_SEC,c); return 0; }
练习2-2
/* 倒计时后显示程序运行时间 */ #include <time.h> #include <stdio.h> /*--- 等待x毫秒 ---*/ void gput(const char* s, int speed){ while (*s) { putchar(*s); fflush(stdout); sleep(speed); *(s++); } } int sleep(unsigned long x) { clock_t c1 = clock(), c2; do { if ((c2 = clock()) == (clock_t)-1) /* 错误 */ return 0; } while (1000.0*(c2 - c1) / CLOCKS_PER_SEC < x); return 1; } int main(void) { int i; clock_t c; char s[128]; printf("输入字符串:"); scanf("%s", s); gput(s, 100); c = clock(); printf("程序开始运行后经过了%.2f秒。经过的时钟数是:%d\n", (double) c / CLOCKS_PER_SEC, c); return 0; }
练习2-3
/* 倒计时后显示程序运行时间 */ #include <time.h> #include <stdio.h> /*--- 等待x毫秒 ---*/ void bput(const char* s,int d,int e,int n){ while (n>0) { printf("%s", s); fflush(stdout); sleep(d); printf("\r "); sleep(e); printf("\r"); n--; } } int sleep(unsigned long x) { clock_t c1 = clock(), c2; do { if ((c2 = clock()) == (clock_t)-1) /* 错误 */ return 0; } while (1000.0*(c2 - c1) / CLOCKS_PER_SEC < x); return 1; } int main(void) { int i; clock_t c; char s[128]; printf("输入字符串:"); scanf("%s", s); bput(s, 1000,1000,3); return 0; }
练习2-4
/* 倒计时后显示程序运行时间 */ #include <time.h> #include <stdio.h> /*--- 等待x毫秒 ---*/ void telop(const char* s,int direction, int speed, int n) { int name_len = strlen(s); int cnt = 0; int i = 0; while (n > 0) { putchar('\r'); for (i = 0; i < name_len; i++) { if (cnt + i < name_len) putchar(s[cnt + i]); else putchar(s[cnt + i - name_len]); } fflush(stdout); sleep(speed); if (direction == 1) { if (cnt > 0) cnt--; else cnt = name_len - 1; } else { if (cnt < name_len - 1) cnt++; else cnt = 0; } n--; } } int sleep(unsigned long x) { clock_t c1 = clock(), c2; do { if ((c2 = clock()) == (clock_t)-1) /* 错误 */ return 0; } while (1000.0*(c2 - c1) / CLOCKS_PER_SEC < x); return 1; } int main(void) { int choice; clock_t c; char s[128]; printf("输入字符串:"); scanf("%s", s); printf("选择从右向左----0.从左向右----1\n"); scanf("%d", &choice); telop(s, choice,1000,3); return 0; }
练习2-5
/* 同时训练扩大水平方向视野的心算训练 */ #include <time.h> #include <stdio.h> #include <stdlib.h> int main(void) { int stage; int a, b, c; /* 要进行加法运算的数值 */ int x; /* 已读取的值 */ int n; /* 空白的宽度 */ clock_t start, end; /* 开始时间·结束时间 */ double Time[11]; double sum = 0; int i = 0; srand(time(NULL)); /* 设定随机数的种子 */ printf("扩大视野心算训练开始!!\n"); for (stage = 0; stage < 10; stage++) { start = clock(); a = 10 + rand() % 10; /* 生成10～99的随机数 */ b = 10 + rand() % 10; /* 〃 */ c = 10 + rand() % 10; /* 〃 */ n = rand() % 17; /* 生成0～16的随机数 */ printf("%d%*s+%*s%d%*s+%*s%d：", a, n, "", n, "", b, n, "", n, "", c); do { scanf("%d", &x); if (x == a + b + c) break; printf("\a回答错误。请重新输入："); } while (1); end = clock(); /* 计算结束 */ Time[stage]=((double)(end - start) / CLOCKS_PER_SEC); sum += Time[stage]; } for ( i = 0; i < stage; i++) { printf("第%d次运算用了%.1f秒\n", i+1, Time[i]); } printf("平均时间是%.1f秒", sum / 10); return 0; }
练习2-6
/* 同时训练扩大水平方向视野的心算训练 */ #include <time.h> #include <stdio.h> #include <stdlib.h> int main(void) { int stage; int a, b, c,choice; /* 要进行加法运算的数值 */ int x; /* 已读取的值 */ int n; /* 空白的宽度 */ clock_t start, end; /* 开始时间·结束时间 */ double Time[11]; double sum = 0; int i = 0; int y = 0;; srand(time(NULL)); /* 设定随机数的种子 */ printf("扩大视野心算训练开始!!\n"); for (stage = 0; stage < 10; stage++) { start = clock(); a = 10 + rand() % 10; /* 生成10～99的随机数 */ b = 10 + rand() % 10; /* 〃 */ c = 10 + rand() % 10; /* 〃 */ n = rand() % 17; /* 生成0～16的随机数 */ choice = rand() % 4; if (choice==0) { printf("%d%*s+%*s%d%*s+%*s%d：", a, n, "", n, "", b, n, "", n, "", c); y = a + b + c; } if (choice == 1) { printf("%d%*s+%*s%d%*s-%*s%d：", a, n, "", n, "", b, n, "", n, "", c); y =a + b - c; } if (choice == 2) { printf("%d%*s-%*s%d%*s+%*s%d：", a, n, "", n, "", b, n, "", n, "", c); y = a - b + c; } if (choice == 3) { printf("%d%*s-%*s%d%*s-%*s%d：", a, n, "", n, "", b, n, "", n, "", c); y = a - b - c; } do { scanf("%d", &x); if (x == y) break; printf("\a回答错误。请重新输入："); } while (1); end = clock(); /* 计算结束 */ Time[stage]=((double)(end - start) / CLOCKS_PER_SEC); sum += Time[stage]; } for ( i = 0; i < stage; i++) { printf("第%d次运算用了%.1f秒\n", i+1, Time[i]); } printf("平均时间是%.1f秒", sum / 10); return 0; }