#include
#include
#include
#define NUM 100
void print(void)     /* 使用说明 */
      { clrscr();
        printf("nnnnntttt Introduction n");
        printf("t*--------------------------------------------------------------*n");
        printf("t*    This program was design for compute linear equations.       *n");
        printf("t*    The way of use it is very simple.                           *n");
        printf("t*    First : Input the number of the equation;(Input 0 to exit) *n");
        printf("t*    Second: Input the coefficient of every eqution;             *n");
        printf("t*    Third : Input the constant of every eqution;                *n");
        printf("t*    Last : Chose the way you want use to solve the equtions; *n");
        printf("t*    That's all, input any key to run it . . .                   *n");
        printf("t*-------------------------By__TJX------------------------------*n");
        getch(); }

void chose(void)    /*选择计算方法*/
    { clrscr();
       fflush(stdin);
        printf("nnnnntt**********Introduction********** n");
                  printf("tt* Chose the way,please.        * n");
                  printf("tt* a : Gauss eliminant.         * n");
                  printf("tt* b : Gauss_yd eliminant.      * n");
          printf("tt* c : Iterative way.           * n");
                  printf("tt* d : Cramer way.              * n");
                  printf("tt* e : exit.                    * n");              
                  printf("tt*************By__TJX************ n");
                  printf("ttPlease choose number :n");}

void input(double **a1,double b1[],int num)    /*数据输入*/
     { int i,j,t;
       double *p;
       char de1,de2;
do{
     printf("Please input array a[%d][%d]: n",num,num);
     printf("Warn: The first number of the array mustn't contain zero! n");
    for(i=1;i