编写一程序，从键盘输入数字R，计算机自动检查在下列算式的（）中能否天上“+”或“—”凑成相应的等式。如能凑成，则打印出这些算式；如凑不成，则给出信息“NO answer！”1（）2（）3（）4（）5（）6（）7（）8（）9=R

给你一个:
#include "stdio.h"

void main()
{   int t;
    int i1,i2,i3,i4,i5,i6,i7,i8;
    int r1,r2,r3,r4,r5,r6,r7,r8;
    char c1,c2,c3,c4,c5,c6,c7,c8;
    int mark=0;
    scanf("%d",&t);
    for(i1=0;i1<2;i1++){/*for1*/
         if(i1==0)
        r1=1+2;
         else
             r1=1-2;
         if(i1==0)
             c1='+';
         else
             c1='-';
        for(i2=0;i2<2;i2++){/*for2*/
          if(i2==0)
                r2=r1+3;
          else
           r2=r1-3;
          if(i2==0)
             c2='+';
         else
             c2='-';
            for(i3=0;i3<2;i3++){/*for3*/
           if(i3==0)
           r3=r2+4;
          else
              r3=r2-4;
          if(i3==0)
             c3='+';
         else
             c3='-';
                for(i4=0;i4<2;i4++){/*for4*/
            if(i4==0)
              r4=r3+5;
          else
              r4=r3-5;   
          if(i4==0)
             c4='+';
         else
             c4='-';
                    for(i5=0;i5<2;i5++){/*for5*/
            if(i5==0)
              r5=r4+6;
          else
              r5=r4-6;   
          if(i5==0)
             c5='+';
         else
             c5='-';
                        for(i6=0;i6<2;i6++){/*for6*/
            if(i6==0)
              r6=r5+7;
          else
              r6=r5-7;        
          if(i6==0)
             c6='+';
         else
             c6='-';
                            for(i7=0;i7<2;i7++){/*for7*/
            if(i7==0)
              r7=r6+8;
          else
              r7=r6-8;            
          if(i7==0)
             c7='+';
         else
             c7='-';
                                   for(i8=0;i8<2;i8++){/*for8*/
                if(i8==0)
                r8=r7+9;
                 else
              r8=r7-9;
                 if(i8==0)
             c8='+';
         else
             c8='-';
         if(r8==t) {
                     printf("1(%c)2(%c)3(%c)4(%c)5(%c)6(%c)7(%c)8(%c)9=%d\n",c1,c2,c3,c4,c5,c6,c7,c8,t);
                     mark=1;
         }
                                }/*for8*/
                            }/*for7*/
                        }/*for6*/
                    }/*for5*/
                }/*for4*/
            }/*for3*/
        }/*for2*/
    }/*for1*/
      
 if(mark==0)
 printf("NO answer!");
}