函数名: qsort 功 能: 使用快速排序例程进行排序 用 法: void qsort(void *base, int nelem, int width, int (*fcmp)()). 程序例: #include #include #include int sort_function( const void *a, const void *b). char list[5][4] = { "cat", "car", "cab", "cap", "can" }.
int main(void) { int x. qsort((void *)list, 5, sizeof(list[0]), sort_function). for (x = 0. x < 5. x ) printf("%s\n", list[x]). return 0. } int sort_function( const void *a, const void *b) { return( strcmp(a,b) ). }
函数名: qsort 功 能: 使用快速排序例程进行排序 用 法: void qsort(void *base, int nelem, int width, int (*fcmp)()). 程序例: #include #include #include int sort_function( const void *a, const void *b). char list[5][4] = { "cat", "car", "cab", "cap", "can" }.
int main(void) { int x. qsort((void *)list, 5, sizeof(list[0]), sort_function). for (x = 0. x < 5. x ) printf("%s\n", list[x]). return 0. } int sort_function( const void *a, const void *b) { return( strcmp(a,b) ). }
函数名: raise 功 能: 向正在执行的程序发送一个信号 用 法: int raise(int sig). 程序例: #include int main(void) { int a, b. a = 10. b = 0. if (b == 0) /* preempt divide by zero error */ raise(SIGFPE). a = a / b. return 0. }
函数名: rand 功 能: 随机数发生器 用 法: void rand(void). 程序例: #include #include int main(void) { int i. printf("Ten random numbers from 0 to 99\n\n"). for(i=0. i<10. i ) printf("%d\n", rand() % 100). return 0. }
函数名: randbrd 功 能: 随机块读 用 法: int randbrd(struct fcb *fcbptr, int reccnt). 程序例: #include #include #include #include int main(void) { char far *save_dta. char line[80], buffer[256]. struct fcb blk. int i, result. /* get user input file name for dta */ printf("Enter drive and file name (no path - i.e. a:file.dat)\n"). gets(line). /* put file name in fcb */ if (!parsfnm(line, &.blk, 1)) { printf("Error in call to parsfnm\n"). exit(1). } printf("Drive #%d File: %s\n\n", blk.fcb_drive, blk.fcb_name). /* open file with DOS FCB open file */ bdosptr(0x0F, &.blk, 0). /* save old dta, and set new one */ save_dta = getdta(). setdta(buffer). /* set up info for the new dta */ blk.fcb_recsize = 128. blk.fcb_random = 0L. result = randbrd(&.blk, 1). /* check results from randbrd */