c - Function inside a function not working -

i have function generate random number in c. works fine when call in main() function. when try call inside function definition returning same number again , again. please help. unable understand reason this.

double uniform_deviate ( int seed ) { return seed * ( 1.0 / ( rand_max + 1.0 ) ); }  int rand_range(int min_n, int max_n) { return  min_n + uniform_deviate ( rand() ) * ( max_n - min_n ); }  int rand_slot(int num_values) { int x; x=rand_range(0,num_values); return x;   }    void main()  {    int x,y;      x=rand_range(0,10) - 'works fine'     y=rand_slot(6) - 'gives 5 output repeatedly'    } 

as following test program shows, both functions work fine, except use same randome seed, everytime run program, give same result. remove comment mark before srand() fix problem.

#include <stdio.h> #include <stdlib.h> #include <time.h>  double uniform_deviate ( int seed ) {     return seed * ( 1.0 / ( rand_max + 1.0 ) ); }  int rand_range(int min_n, int max_n) {     return  min_n + uniform_deviate ( rand() ) * ( max_n - min_n ); }  int rand_slot(int num_values) {     int x;     x=rand_range(0,num_values);     return x;  }   int main() {     int x,y,i;       //srand(time(null));     (i = 0; < 10; i++) {         x=rand_range(0,10);         y=rand_slot(10);         printf("i = %d : %d %d\n", i, x, y);     }      return 0; } 

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run result:

$ ./a.out  = 0 : 8 3 = 1 : 7 7 = 2 : 9 1 = 3 : 3 7 = 4 : 2 5 = 5 : 4 6 = 6 : 3 5 = 7 : 9 9 = 8 : 6 7 = 9 : 1 6 

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this test program used show 2 functions give same number list:

#include <stdio.h> #include <stdlib.h> #include <time.h>  double uniform_deviate ( int seed ) {     return seed * ( 1.0 / ( rand_max + 1.0 ) ); }  int rand_range(int min_n, int max_n) {     return  min_n + uniform_deviate ( rand() ) * ( max_n - min_n ); }  int rand_slot(int num_values) {     int x;     x=rand_range(0,num_values);     return x;  }   int main() {     int x,i;      srand(1);     (i = 0; < 10; i++) {         x=rand_range(0,10);         printf("i = %d : %d\n", i, x);     }      printf("\n\n");      srand(1);     (i = 0; < 10; i++) {         x=rand_slot(10);         printf("i = %d : %d\n", i, x);     }      return 0; } 

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run result:

$ ./a.out  = 0 : 8 = 1 : 3 = 2 : 7 = 3 : 7 = 4 : 9 = 5 : 1 = 6 : 3 = 7 : 7 = 8 : 2 = 9 : 5   = 0 : 8 = 1 : 3 = 2 : 7 = 3 : 7 = 4 : 9 = 5 : 1 = 6 : 3 = 7 : 7 = 8 : 2 = 9 : 5