Summary of pseudo-random numbers in C language

1. Requirement: Random number between output [X, Y]
   

2. Algorithm: rand ()% (y-x+1) +x

#include  <stdio.h> #include  <stdlib.h> #include  <time.h> #include  <sys/ time.h>//interchange function Void swap (INT&NBSP;*A,&NBSP;INT&NBSP;*B) {    int temp= 0;     temp = *a;    *a = *b;     *b = temp;} The sum of the corresponding arrays of the two random numbers [20,40] array is stored in the third array. And do bubble sort. Int main (void) {    int a[10] = {0},          b[10] = {0},        c[10] =  {0};    int i = 0, j = 0;     Struct timeval timenow;    gettimeofday (&timenow, null);     srand (timenow.tv_usec);  //the current time,  the microsecond level as a seed.     for  (i = 0; i < 10; i++) {         a[i] = rand ()%21+20;        b[i] =  Rand ()%21+20;        c[i] = a[i] + b[i];         printf ("%d + %d = %d\n", A[i],b[i],c[i]);     }        printf ("Start bubbling sort: \ n");     for (i = 0; i< 10 -1; i++) {         for (j = 0; j< 10 -1 -i; j++) {             if (c[j] < c[j+1])                  swap (&c[j], &c[j+1]);         }    }    for (i = 0; i < 10; i++) {        printf ("c[%d] = %d\n", I,c[i]);    }     return 0;}

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Summary of pseudo-random numbers in C language